I wanted to learn how to use Kimono, Bop.fm, and embedly all while maintaining a realtime app so I made a meteor.js app that allows a user to tweet at someone with an artist and a song and that song will be played over the web powered by Bop.fm.
The target user would be anyone who runs social events or places. If you're at a party or at a bar and want the people there to be more involved in maintaining the ambiance through music then this web app will help.
I'm the most proud of the api that I built with Kimono. It grabs what I want very consistently and works very reliably. I am also proud of how it is realtime although that's not hard with Meteor.