Keezy is a very minimalist in its look with just 8 colored buttons. That's it. Each button allows you to record a loop, which you can then mix together into your own masterpiece. If need be you can also delete or undo individual tracks if you want. Apparently, in the beta for the app the biggest users have been musicians (obviously), but also children. It seems that kids like to just yell or make rude noises into the app and mix those together.
Keezy has a solid pedigree as well. The app is made by Elepath which is the app development outfit started by Vimeo founder Jake Lodwick. Elepath is also behind one of the better bucketlist to-do apps for iOS, Thinglist. So, you know that Keezy has talented developers behind it.
Download: Keezy (iOS only)