The Particle Physics Simulator is a physics application for Android powered devices (v2.2+) in which real gravitational systems of particles can be created, simulated and interacted with in real time. It is an n-body particle simulator where the behaviour of the system is driven only by each particle's gravity and its interaction with all the other particles in it. It is turning more into a physics playground lately though, with the addition of accelcerometer support, elastic collisions, ability to create walls, anti-particles and more.

You can try it out right here in your browser using the AppSurfer emulator below:

You can download the application from the Android Market here. If you like it very much you can even buy me a beer!