Data.Gov - The Obama Administration launched Data.gov to try to provide more government data in easy-to-use open formats like XML, CSV, and KML. It looks like Google is starting to use it already.

listed in: data, google, information, politics | ∞

Wordle - Make tag clouds from any text document.

listed in: data, tags | ∞

We Feel Fine - This is probably one of the coolest twitter/graph mashups I've seen. See how people are feeling, sortable by location, age, or gender, and displayable in 5 different formats.

listed in: data, twitter | ∞

Freebase - Giant open-source (Wikipedia-like) database of facts that you can run pseudo-MySQL queries on. Used to build a video of the 'Wal-Mart Infection' across the US. Might be something worth learning...

listed in: data, open source | ∞

Flight Patterns - Amazing video created using data from US flight patterns.

listed in: art, data, video, visualization | ∞