BT Controller v1.4

BT Controller allows you to use android devices as gamepad controllers for any
other android device.
For example, you can play a snes emulator on your tablet which is connected to a
tv, using your phone as the controller. It also works the other way around, you
can use your tablet as a controller [...]

More: http://mobilehere.net/2012/09/bt-controller-v1-4.html