Google

AndroidGlobalTime
AndroidGlobalTime is a 3D world clock and may serve as an illustrative example of how to use the OpenGL ES APIs in an Android applications.

Note Pad
Note Pad is another sample application from Google. It features a simple text processor and lists all noted in a linear structure.

Lunar Lander
Lunar Lander is yet another sample game, which was extracted from the Android's SDK. It showcases a simple 2D graphic implementation on this platform

Snake
Snake is the first ever publicly released application for the Android mobile platform. It was included in the Android SDK as a sample application.