The one and only vibraphone/marimba/xylophone app for the Android platform. You can play it with mallets which you can make yourself.
The Kalimba, also called Karimba, Thumb Piano, Lamellophone, Mbira, Sanza, among others, is a musical instrument from southern Africa. The keys are plucked with thumb or fingers, and the vibrations are amplified by a hollow box resonator or sounding board.
Tilt Theremin is an approximation of the Theremin musical instrument for Android phones. You can play your favourite songs on it by waving the phone from side to side in the air. Check out how to play the Star Trek Theme using it: