Dividuum has found a way to use RFID tags with a reader to store and play back music.

SID-files are stored on RFID tags. When you put the tag near the reader, the music is played on the stereo.

A stack of tags placed near the reader will act as a playlist. Remove one of the playing tag, and the program will play the next SID-File in the stack.

Video and pics.

Via Unmediated Hackaday.