I've got two going :)
https://shepherd.com/
Building a really unique book recommendation platform to help readers find books they might not otherwise know about. We just started working on a full book app that will be a private book diary, along with recommendations and insights based on your Book DNA. Think Goodreads, but rebuilt for readers who want a private space to track what they read, keep notes, and get truly personalized book recommendations (like Pandora or Spotify for books).
https://downforeveryoneorjustme.com/
This is a fun one I do with a good friend. Basically, to see if a website is down, or if it is just you, along with reported reasons from the community. We are working to add user accounts so you can create your own custom lists of websites/services to track.