diff --git a/README.md b/README.md
index 4c38414..9123ee5 100644
--- a/README.md
+++ b/README.md
@@ -78,6 +78,21 @@ then the round resolves; turn-at-a-time games fit as the case where one
 seat needs input at a time. A game of single commands with out-of-turn
 interruptions, Wiz-War's shape, does not fit and keeps its own server.
 
+## The hall-wide notice
+
+Every game on the shared host shows the same notice at the top of its
+pages when there is one: maintenance, a new game, anything the whole
+family should hear. The keeper sets it on the host,
+
+    hall-announce "Kestrel's Hall is down for five minutes of maintenance" --at "2026-09-30 11:00 UTC"
+    hall-announce --clear
+
+which writes /var/lib/hall/announcement.json; each game's site serves it at
+`/hall/announcement.json` (a `handle_path` in its Caddy site file), and
+`Announcement.svelte`, in the template's layout, shows it with the time in
+each reader's own clock. A reader may dismiss one notice; the next still
+shows. `hall-announce` is installed by `gamehall/deploy.sh`.
+
 ## The family
 
 `family.json` lists every game of Kestrel's Hall: slug, name, address,
diff --git a/drift.sh b/drift.sh
index 2ce6c28..28b74c5 100755
--- a/drift.sh
+++ b/drift.sh
@@ -12,7 +12,7 @@ KIT="$(cd "$(dirname "$0")" && pwd)"
 MAP="$KIT/drift-map/$SLUG.txt"
 SHARED="server/src/index.ts server/src/rooms.ts server/src/store.ts server/src/reports.ts server/src/ratelimit.ts server/src/tally.ts
 src/lib/game/spec.ts src/lib/net/client.ts src/lib/net/talk.ts src/lib/net/view.ts src/lib/net/room.svelte.ts
-src/lib/components/TableTalk.svelte src/lib/components/ReportSlip.svelte src/lib/components/TabbedDialog.svelte src/lib/components/Tabs.svelte
+src/lib/components/TableTalk.svelte src/lib/components/ReportSlip.svelte src/lib/components/TabbedDialog.svelte src/lib/components/Tabs.svelte src/lib/components/Announcement.svelte
 deploy/deploy.sh deploy/setup-droplet.sh deploy/setup-server.sh deploy/Caddyfile.tmpl deploy/verify-ledgers.sh
 deploy/replay-ledgers.ts deploy/pulse.sh deploy/visitors.sh deploy/sentry-slack-alert.sh deploy/pull-reports.sh deploy/report-reply.sh
 deploy/__SLUG__.service deploy/__SLUG__.cron deploy/__SLUG__-backup.sh deploy/__SLUG__-rollup.sh"
diff --git a/gamehall/deploy.sh b/gamehall/deploy.sh
index 04fe789..b0b800f 100755
--- a/gamehall/deploy.sh
+++ b/gamehall/deploy.sh
@@ -23,6 +23,9 @@ ssh "root@$HOST" '
   install -m 755 /tmp/gamehall-ops/gamehall-rollup.sh /usr/local/bin/gamehall-rollup.sh
   install -m 644 -D /tmp/gamehall-ops/traffic.py /usr/local/lib/gamehall/traffic.py
   install -m 644 /tmp/gamehall-ops/gamehall.cron /etc/cron.d/gamehall
+  # The hall-wide notice every game serves at /hall/announcement.json.
+  install -m 755 /tmp/gamehall-ops/hall-announce.sh /usr/local/bin/hall-announce
+  install -d -m 755 /var/lib/hall
   mkdir -p /var/lib/gamehall /var/log/gamehall
   rm -r /tmp/gamehall-ops
 '
diff --git a/gamehall/gamehall.caddy b/gamehall/gamehall.caddy
index eb8d1e3..0ef7e7f 100644
--- a/gamehall/gamehall.caddy
+++ b/gamehall/gamehall.caddy
@@ -1,5 +1,12 @@
 # Kestrel's Hall, the front door of the family: a static page, no server.
 gamehall.kestrelsnest.social, gamehall.159.203.115.252.sslip.io {
+	# The hall-wide notice (hall-announce on the host): one file, served by every game's site.
+	handle_path /hall/* {
+		root * /var/lib/hall
+		header Cache-Control "no-store"
+		file_server
+	}
+
 	root * /opt/gamehall
 	encode gzip zstd
 
diff --git a/gamehall/ops/hall-announce.sh b/gamehall/ops/hall-announce.sh
new file mode 100644
index 0000000..87644ab
--- /dev/null
+++ b/gamehall/ops/hall-announce.sh
@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+# The notice every game of Kestrel's Hall shows at the top of its pages.
+# Each site serves /var/lib/hall/announcement.json at /hall/announcement.json;
+# a page checks it on load and every few minutes. Run on the host as root:
+#   hall-announce "Kestrel's Hall is down for five minutes of maintenance" --at "2026-09-30 11:00 UTC" [--until "2026-09-30 11:15 UTC"]
+#   hall-announce --show
+#   hall-announce --clear
+# --at is when it happens, told in each reader's own time; --until is when the
+# notice stops showing (an hour after --at when not given).
+set -euo pipefail
+FILE=/var/lib/hall/announcement.json
+
+case "${1:-}" in
+  --clear) rm -f "$FILE"; echo "cleared."; exit 0 ;;
+  --show) cat "$FILE" 2>/dev/null || echo "no announcement."; exit 0 ;;
+  ''|-*) sed -n '2,9p' "$0" | sed 's/^# \{0,1\}//'; exit 2 ;;
+esac
+
+TEXT="$1"; shift
+AT=""; UNTIL=""
+while [ $# -gt 0 ]; do
+  case "$1" in
+    --at) AT="$(date -u -d "$2" +%Y-%m-%dT%H:%M:%SZ)"; shift 2 ;;
+    --until) UNTIL="$(date -u -d "$2" +%Y-%m-%dT%H:%M:%SZ)"; shift 2 ;;
+    *) echo "unknown option: $1" >&2; exit 2 ;;
+  esac
+done
+[ -n "$AT" ] && [ -z "$UNTIL" ] && UNTIL="$(date -u -d "$AT + 1 hour" +%Y-%m-%dT%H:%M:%SZ)"
+
+mkdir -p "$(dirname "$FILE")"
+# A new id each time, so a reader who dismissed the last notice still sees this one.
+TEXT="$TEXT" AT="$AT" UNTIL="$UNTIL" ID="$(date -u +%Y%m%dT%H%M%S)" python3 -c '
+import json, os
+a = {"id": os.environ["ID"], "text": os.environ["TEXT"]}
+if os.environ["AT"]: a["at"] = os.environ["AT"]
+if os.environ["UNTIL"]: a["until"] = os.environ["UNTIL"]
+print(json.dumps(a))' > "$FILE.tmp"
+chmod 644 "$FILE.tmp"
+mv "$FILE.tmp" "$FILE"
+cat "$FILE"
diff --git a/gamehall/site/index.html b/gamehall/site/index.html
index c2c2b1e..a3c00e5 100644
--- a/gamehall/site/index.html
+++ b/gamehall/site/index.html
@@ -113,6 +113,9 @@
 
   footer { margin-top: 64px; padding: 28px 0 48px; border-top: 1px solid var(--line); color: var(--bone-faint); font-size: 0.9rem; }
   footer p { margin: 0 0 8px; }
+/* The hall-wide notice: its own colors, the same in every game of the hall. */
+.hall-announcement { position: sticky; top: 0; z-index: 1000; display: flex; align-items: center; justify-content: center; gap: .8rem; padding: .45rem 2.4rem .45rem 1rem; background: #f2c45a; color: #1d1a12; font: 500 .95rem/1.35 system-ui, -apple-system, 'Segoe UI', sans-serif; text-align: center; box-shadow: 0 1px 4px #0005; }
+.hall-announcement button { position: absolute; right: .5rem; background: none; border: 0; color: inherit; font-size: 1.3rem; line-height: 1; padding: .2rem .5rem; cursor: pointer; }
 </style>
 </head>
 <body>
@@ -214,5 +217,50 @@
   </footer>
 
 </div>
+<script>
+// The hall-wide notice every game of Kestrel's Hall shows (hall-announce on the
+// host): checked on load, every few minutes, and when the page is looked at
+// again; a reader may dismiss one, and the next still shows.
+(() => {
+	const KEY = 'hall:dismissed';
+	let bar = null;
+	let current = null;
+	const read = () => { try { return localStorage.getItem(KEY); } catch { return null; } };
+	function when(at) {
+		const t = at ? Date.parse(at) : NaN;
+		if (!Number.isFinite(t)) return '';
+		const minutes = Math.round((t - Date.now()) / 60000);
+		if (minutes > 90) return ` (${new Date(t).toLocaleString([], { weekday: 'short', hour: 'numeric', minute: '2-digit' })}, your time)`;
+		if (minutes > 1) return ` (in ${minutes} minutes, at ${new Date(t).toLocaleTimeString([], { hour: 'numeric', minute: '2-digit' })})`;
+		return minutes >= -15 ? ' (now)' : '';
+	}
+	function show() {
+		const a = current;
+		const live = a && a.id !== read() && !(a.until && Date.parse(a.until) < Date.now());
+		if (!live) { bar?.remove(); bar = null; return; }
+		if (!bar) {
+			bar = document.createElement('div');
+			bar.className = 'hall-announcement';
+			bar.setAttribute('role', 'status');
+			bar.innerHTML = '<span></span><button type="button" aria-label="Dismiss this announcement">×</button>';
+			bar.querySelector('button').onclick = () => { try { localStorage.setItem(KEY, current.id); } catch {} show(); };
+			document.body.prepend(bar);
+		}
+		bar.querySelector('span').textContent = a.text + when(a.at);
+	}
+	async function check() {
+		try {
+			const res = await fetch('/hall/announcement.json', { cache: 'no-store' });
+			const a = res.ok ? await res.json() : null;
+			current = a && typeof a.text === 'string' && a.text && typeof a.id === 'string' ? a : null;
+		} catch {}
+		show();
+	}
+	check();
+	setInterval(check, 5 * 60000);
+	setInterval(show, 30000);
+	document.addEventListener('visibilitychange', () => { if (document.visibilityState === 'visible') check(); });
+})();
+</script>
 </body>
 </html>
diff --git a/template/deploy/Caddyfile.tmpl b/template/deploy/Caddyfile.tmpl
index 1a39223..9b270fb 100644
--- a/template/deploy/Caddyfile.tmpl
+++ b/template/deploy/Caddyfile.tmpl
@@ -1,4 +1,11 @@
 __HOST__ {
+	# The hall-wide notice (hall-announce on the host): one file, served by every game's site.
+	handle_path /hall/* {
+		root * /var/lib/hall
+		header Cache-Control "no-store"
+		file_server
+	}
+
 	root * /opt/__SLUG__/build
 	encode gzip zstd
 
diff --git a/template/src/lib/components/Announcement.svelte b/template/src/lib/components/Announcement.svelte
new file mode 100644
index 0000000..18f343f
--- /dev/null
+++ b/template/src/lib/components/Announcement.svelte
@@ -0,0 +1,119 @@
+<script lang="ts">
+	// The host's announcement, shown by every game of Kestrel's Hall: the keeper
+	// writes /var/lib/hall/announcement.json on the host (hall-announce), and each
+	// game's site serves it at /hall/announcement.json. It is checked when the page
+	// loads, every few minutes, and whenever the page is looked at again. A reader
+	// may dismiss one announcement; the next one still shows.
+	import { onMount } from 'svelte';
+
+	interface Announcement {
+		/** Names this announcement, so dismissing it does not hide the next. */
+		id: string;
+		text: string;
+		/** When what it announces happens, told in each reader's own time. */
+		at?: string;
+		/** After this it is no longer shown. */
+		until?: string;
+	}
+
+	const SOURCE = '/hall/announcement.json';
+	const CHECK_MS = 5 * 60_000;
+	const DISMISSED = 'hall:dismissed';
+
+	let current = $state<Announcement | null>(null);
+	let dismissed = $state<string | null>(null);
+	let now = $state(Date.now());
+
+	async function check() {
+		try {
+			const res = await fetch(SOURCE, { cache: 'no-store' });
+			const a: unknown = res.ok ? await res.json() : null;
+			current = a && typeof a === 'object' && typeof (a as Announcement).text === 'string' && (a as Announcement).text && typeof (a as Announcement).id === 'string' ? (a as Announcement) : null;
+		} catch {
+			// No announcement reachable: none shown.
+		}
+		now = Date.now();
+	}
+
+	onMount(() => {
+		try {
+			dismissed = localStorage.getItem(DISMISSED);
+		} catch {
+			// Without storage a dismissal lasts this visit.
+		}
+		void check();
+		const poll = setInterval(check, CHECK_MS);
+		const tick = setInterval(() => (now = Date.now()), 30_000);
+		const looked = () => {
+			if (document.visibilityState === 'visible') void check();
+		};
+		document.addEventListener('visibilitychange', looked);
+		return () => {
+			clearInterval(poll);
+			clearInterval(tick);
+			document.removeEventListener('visibilitychange', looked);
+		};
+	});
+
+	const shown = $derived(current && current.id !== dismissed && !(current.until && Date.parse(current.until) < now) ? current : null);
+
+	/** When it happens, in the reader's own clock: "in 25 minutes, at 7:00 AM", or the day and time further off. */
+	const when = $derived.by(() => {
+		const t = shown?.at ? Date.parse(shown.at) : NaN;
+		if (!Number.isFinite(t)) return '';
+		const minutes = Math.round((t - now) / 60_000);
+		if (minutes > 90) return ` (${new Date(t).toLocaleString([], { weekday: 'short', hour: 'numeric', minute: '2-digit' })}, your time)`;
+		if (minutes > 1) return ` (in ${minutes} minutes, at ${new Date(t).toLocaleTimeString([], { hour: 'numeric', minute: '2-digit' })})`;
+		return minutes >= -15 ? ' (now)' : '';
+	});
+
+	function dismiss() {
+		// Taken first: once dismissed, nothing is shown.
+		const id = shown?.id;
+		if (!id) return;
+		dismissed = id;
+		try {
+			localStorage.setItem(DISMISSED, id);
+		} catch {
+			// The dismissal still holds for this visit.
+		}
+	}
+</script>
+
+{#if shown}
+	<div class="hall-announcement" role="status">
+		<span>{shown.text}{when}</span>
+		<button type="button" aria-label="Dismiss this announcement" onclick={dismiss}>×</button>
+	</div>
+{/if}
+
+<style>
+	/* Its own colors, not the game's: the same notice reads the same in every game of the hall. */
+	.hall-announcement {
+		position: sticky;
+		top: 0;
+		z-index: 1000;
+		display: flex;
+		align-items: center;
+		justify-content: center;
+		gap: 0.8rem;
+		padding: 0.45rem 2.4rem 0.45rem 1rem;
+		background: #f2c45a;
+		color: #1d1a12;
+		font: 500 0.95rem/1.35 system-ui, -apple-system, 'Segoe UI', sans-serif;
+		text-align: center;
+		box-shadow: 0 1px 4px #0005;
+	}
+
+	button {
+		position: absolute;
+		right: 0.5rem;
+		background: none;
+		border: 0;
+		color: inherit;
+		font-size: 1.3rem;
+		line-height: 1;
+		padding: 0.2rem 0.5rem;
+		cursor: pointer;
+	}
+</style>
diff --git a/template/src/routes/+layout.svelte b/template/src/routes/+layout.svelte
index b93e9ba..33c1fca 100644
--- a/template/src/routes/+layout.svelte
+++ b/template/src/routes/+layout.svelte
@@ -1,7 +1,9 @@
 <script lang="ts">
 	import '../app.css';
+	import Announcement from '$lib/components/Announcement.svelte';
 
 	let { children } = $props();
 </script>
 
+<Announcement />
 {@render children()}