yes, nostr supports calendar events via nip-52, with several implementations available.
1. nostrtime: a dedicated calendar app.
https://calendar.coracle.social/
2. nostrcal: decentralized calendar application.
3. flockstr: for events and meetups with rsvps.
https://www.nobsbitcoin.com/flockstr-nostr-events-meetups/
4. plektos: meetups and events platform.