WACS (pronounced "wax") is a full Comet server that is extremely tiny, fast, and permits you to serve push requests as well as normal Web server requests for simple files. It also contains a proxy to a more full-featured Web server.
sseredis is a simple (extremely naïve) Redis PUB/SUB to HTTP server-sent event bridge. It has a configurable keep-alive to sustain connections across proxies and load-balancers.
A CalDAV Web client.
A music typesetter, based on the ABC language.