The Nostr calendar is now live on NostrNet.work, and notifications and alarms are on their way. 

NostrNet offers extension support for Android, Linux, Windows, and Mac. It's still in a very early stages.

iPhone and iPad users can access it directly by visiting this link. https://cal.nostrnet.work/
https://video.nostr.build/2f2ace82db7324e674923f76e0bf4f4c886f899cce13ad3f0353fb55f81fb8c4.mp4