Jordi Parra's Spotify Box is a wonderful reworking of the mix-tape and the radio, all in a hot little Dieter Rams-inspired box.
It works like this. The "radio" part has (or will have) a Wi-Fi connection and runs the Spotify music-streaming service using libspotify on embedded Linux. The radio comes with a clutch of tiny RFID disks. These can be tied to any Spotify track or playlist, so when you pop them into the little RFID-reading circle on the front of the box, music starts to play. Buttons on the faceplate let you skip tracks.