I like working on open source projects. Here is a few that I've either started or contributed a significant amount of work to. There is a more complete list on my Ohloh page.
- Acoustid - Audio fingerprint database
- Database Modeller - Simple tool for drawing entity-relational diagrams
- Bazaar plugins - Some plugins for the Bazaar version control system
- TagLib - C++ library for reading/writing metadata in audio files
- Picard - MusicBrainz-based audio file tagger
- Lots of other MusicBrainz projects