I hear today is the TechCrunch hackathon!
If you're looking for something to do, how about picking off one of the ideas on the roadmap for the open Twitter-like ecosystem.
You could do a nice linkblogging tool. Or a beautiful rendering of river.js in the browser of your choice (or hopefully all of them).
How about a nice way to manage susbscription lists in a way that can be shared with all applications. One place where users can subscribe or unsubscribe.
Remember to give your users' data to other apps, to be part of an ecosystem. Closed silos are for the big guys. It's how we disrupt them, by working together. :-)