In Rock Band 2 there is freestyle mode where you can play whatever you
want. If you don't have RB2 then you can download a programme called
Drum Machine located here
http://andrewrudson.com/drummachine/main.php
Install it and plug in your rock band kit to your pc, load up the
programme and your set. You can assign differnet sounds to different
pads if you wish and also record yourself. Be warned though that using
a rock band kit as a real kit it pretty crap TBH.
constipated people dont give a crap