Duet Display - With Duet Display, you can transform your iPhone or iPad into a second display to expand the screen space of your PC or Mac system.
Fluid Simulation - Relax with beautiful, fluid particle effects that react to your touch.
iDisplay - iDisplay is an app that turns a mobile device into a secondary desktop monitor. The app currently supports iOS, Android, Windows and MacOS, and it lets users connect a desktop computer to a mobile device over WiFi. Read more about iDisplay.
Particlescape - Particlescape app lets you create stunning patterns at your fingertips.
Luna Display - Hardware that turns the iPad into a wireless second display
TripleA - TripleA is a free (under GPL) turn based strategy game based on Axis & Allies board game.