RetwisJS is a project mainly written in ..., it's free.
Port of Redis's Twitter clone, retwis for node.js
A port of the twitter clone Retwis provided by Redis documentation written on node.js
Relevant links
http://redis.io/topics/twitter-clone http://redis.io/ http://nodejs.org/ http://jade-lang.com/ http://expressjs.com/ https://github.com/mranney/node_redis