Users can tap any button to create a downbeat (behind the scenes, a sequencer flips to "on"), which will rise in unison with the music until you tap it once more to settle it (and in turn, eliminate said beat). You can grab hold of a peg in order to sustain a given note until you let it loose. There's a few pitch / tone buttons that serve an extra purpose -- one that we're sure you can guess by their names. Those are capable of spinning left and right, with pitch shifting and speeds increasing / decreasing with your movements. The learning curve here is practically nonexistent, and while folks at the booth had no hard information regarding an on-sale date, they confirmed to us that hawking it is most certainly on the roadmap... somewhere. Head on past the break for your daily (video) dose of cacophony.
PocoPoco musical interface box at SIGGRAPH 2011