A few weeks ago I shipped a feature I'd been putting off because it felt like it needed a backend: subscribable calendar feeds. "Add this holiday to Google Calendar. " "Subscribe to all your country's public holidays so they show up in Apple Calendar forever.
Source: [Dev.to](https://dev.to/mark_b5f4ffdd8e7cd58/generating-valid-ics-calendar-feeds-at-build-time-50lp)