So you want to build your own robot to play the piano, move things, and get things done around your home? This project helps you get started. The Multipurpose Mobile Manipulator is an open source human-size robotics platform that can be taught to perform tasks.
The robot has a laptop for its face, extensible arms, large servos, and adaptable grippers. There is also a mobile base that lets the robot navigate a room. You are going to need a laptop computer, Arduino Mega, dual motor driver, laptop computer, computer fans, and a few other parts to get started. More information is available here.