Comment by continuational

- An alarm clock with a single-click wake up time picker for Android, back when my schedule was unpredictable.

- Several games (for DOS, TI-83+, and later Windows or the browser).

- A wiki.

- A chatroom for our Tremulous clan.

- A forum for our travel group.

- Several programming languages - currently working on one as well.

- A budget tool that would take my transactions and group them.

- A web framework for Scala based on React.

Some with friends, some alone. Plus, as it goes, a bunch of things that never reached a usable state.