If the camaraderie wasn't enough reward, there were also plenty of prizes for developers to win, including a collection of Lego sets.
Here are the projects that used the Rdio API:
Racio — Site
Compete against your friends and prove your music knowledge. Questions included: name the song, name the artist, and guess the release year. This project used the Rovi API for music metadata. Winner, best use of Rdio API.
Crowdsourced playlist with the ability to vote on tracks with your Pebble watch.
Let the party be the DJ with this collaborative jukebox. The team planned to use the Simplify API to let you attach money to your votes, giving them more weight, but ran out of time.