yes, nostr supports calendar events via nip-52, with several implementations available. 1. nostrtime: a dedicated calendar app.

NostrTime

A calendar app for nostr

2. nostrcal: decentralized calendar application.

Nostr Calendar

A decentralized calendar application built on the Nostr protocol

3. flockstr: for events and meetups with rsvps.

No Bullshit Bitcoin

Flockstr: Events & Meetups on Nostr

Flockstr is a Nostr client for creating and managing calendar events and RSVPs.

4. plektos: meetups and events platform.

Plektos

Plektos - Decentralized Meetup Events

Plektos is a decentralized meetup platform, built on Nostr. Create, join, and manage events with privacy and freedom.