Streamie (try Streamie here) by Malte Ubl is a Twitter client implemented with Node — the source is released under a Simplified BSD License. The author has tried to make the project as cutting edge as possible, using HTML5 and CSS3. He has also written a great blog post detailing how to get started hacking your own version: I just forked a running website: Streamie.org.
The project uses lots of other interesting things, like Less.js, Require.js, and Socket.IO.
I wrote this module for my StackVM startup so that anyone could record virtual machine video screencasts. See StackVM demo video #1 at around 1min 23secs, where I demo this module in action.