The N-Body Live Wallpaper is an application for Android (v2.1+) powered devices that enables the user to have a particle zoo of gravity interactions as a home screen wallpaper. The application is heavily based on the first version fo the Particle Physics Simulator, but adapted to suit a live wallaper needs. Features:

• Real n-body simulation, pure gravitational interactions between particles.
• Allow or not phisically realistic collisions and mergers between particles.
• Set particle and background colors.
• Set gravity strength and particle mass.
• Accelerometer support.
• Shoot particles or create repulsive forces using touchscreen.
• Enable the action to expand beyond your screen limits without losing particles.
• Enable or disable the central black hole which exerts a neat attractive force towards the center.
• Enable or disable particle trails (disable to improve performance).

Take into account we're talking about a real n-body simulation. I recommend keeping the number of particles reasonably low for the live wallpaper version (about 10-20), even though it only executes when the screen is on. Does not drain your battery keeping loops or listeners when sleeping. Give it a try, download it from the Android Market!