Musical robots have gotten a lot of coverage online in the past few years. They can play all kinds of musical instruments, including the piano, guitar, and drums. MegCell has already introduced an Arduino powered self-playing robot guitarist on Kickstarter. It uses a PC or smartphone to process music sheets. Bruce is also working on a robot drummer.
This is a robotic arm that uses two styluses to play drums on an iPad. The above video shows it in action. You can make this project happen by supporting it on Kickstarter.[HT]