A simple clock displaying an approximate percentage of Americans (and now, other people!) currently awake.
You can install the site as a PWA in-browser, or more usefully on iOS or Android. On iOS, open in Safari and select the share icon, then Add to Home Screen.
Idea shamelessly stolen from Yusuf Bouzekri, whose "Are the Americans Awake?" clock prompted this re-build and expansion of the concept.