Tovbot's Shimi made its first public appearance two days ago at Google I/O, where not just one but three Shimis performed in perfect coordination. Tovbot was formed earlier this year
by a group of robot researchers and entrepreneurs hailing from Georgia Tech, IDC in Israel, and MIT Media Lab. [Their] goal is to foster a new paradigm of personal robots - robots that don't just clean your floors or your pool, but also interact with you on a personal, almost human level. According to a news item on Georgia Tech's website,
Shimi, a musical companion developed by Georgia Tech’s Center for Music Technology, recommends songs, dances to the beat and keeps the music pumping based on listener feedback. Automaton has more detail.