How about going outside with PianoHop to play with real birds singing in a park?
The PianoHop is a tiny Piano with small birds hopping on keyboards. A bird rotates with a keyboard you are playing.
Horizontal orientation of birds is set using the accelerometer.
Hopping speed is changed by touching Slow/Fast label shown on the screen.
iOS 4.3.5 or later.
iPad2, iPad, iPhone 3GS or later, and iPod touch 4 or later.