A few notable hacks at TechCrunch Disrupt, currently ongoing at the Concourse in San Francisco.
FAGicon is Tetris in your favicon, by some weird Russian dudes. How does it work? I don't know, but it does. Try the link on HackerNews.
eccube is a very trippy Processing.js game which interacts with music (via the Echo Nest API), from the good folks at Bloom.
WeatherChecker adds weather to your Google Calendar. Did you know WUnderground has an API? More weather mashups are afoot; I can feel it in my little toe.
Germanita was the only hardware project at Disrupt, by yours truly and co-hacker Erik Swedberg. It implements the DMX protocol with an Arduino to drive lighting from a web application, based on music analysis from Echo Nest.
BridgeWater Disrupt was not in the Hackathon, but nonetheless a very cool project by two guys from the Bridgewater Associates hedge fund. Not only is it a virtual market for trading "shares" of presenting startups, but it offers an API for writing automated trading agents.
There's a writeup about hackathons in yesterday's Wall Street Journal, whence the photo above. Happy hacking!