When you just need to Slack from the command line: "Slacker" is a simple weekend project CLI interface to Slack. Slacker isn't a production-ready tool, but perhaps it will be one day. If you live in tmux or the command line like me, you might find this a fun, curious little project.
The Botanist -- a long-term side project of mine -- is a 2D fantasy RPG intended for release on multiple platforms, including web, Android and iOS. The game features an immersive universe with deep supporting mythology and lore; a relative rarity among mobile games.
Perhaps the only of its kind, morsecode.me is a live, online Morse code radio; the most arcane of chat rooms. Users can communicate with one another only by keying Morse. Fortunately the site also comes with a cheat sheet and live translation.
SiteChat, now retired, was a popular chat app available in the Chrome web store. The extension turned every website into a unique chatroom, and quickly grew in popularity. I wrote an interesting postmortem that describes the rise and fall of SiteChat as a society.