From my ideas and views of the title, it'll have as follows.
1 - A full fledged drum kit, to which you can optionally bang away, or play the drums along to music that'll play and the notes appearing above.
2 - The drum kit again, but with 2 players etc, going at the same time, yada yada.
3 - The top picture as you see, where you can move your hand around, making them play fast, slow, etc etc, even write and compose your own music, etc.
Apart from that, and what I have seen, can't think of anything / much more.
19/12/2006 / Victoria, Melbourne, Frankston