This is pretty darn amazing. Moog just recently released a $30 iOS app that simulates a $10,000 Moog Model 15 Synthesizer. And by all accounts so far, it does the job really well. This is the amazing thing about tablets and touchscreen capabilities -- you basically have the functionality of a full-fledge console instrument (a huge one at that) that can fit in your backpack -- flat!
Moog uploaded a bunch of samples of what you can do with this amazing $30 app. Case in point, you can do anything. Just listen. Then download the app here!