I have a drum set app on my phone. It has different pads that represent all the different drum sounds and the sounds fire every time you touch the pad. It works surprisingly well. You can make some pretty cool beats with just your fingers.
But in the same way that playing guitar hero is not at all like playing the guitar, my digital drum kit is nothing like playing the drums. It is all in the fingers so there is none of the coordination between the hand and the foot.