Just a solid white screen, with additional colors available via the touchscreen. I use it as a flashlight.
Slide your finger around in the top third, middle third, or bottom third of the screen to change red, green and blue components of the color.
The app can be set to keep the screen on, to automatically increase the screen brightness to maxium, and to only show white (disable color changes).
v4: Added settings screen with options to control auto-brightness, keep screen on, and only show white.
v3: Removed title bar for even more whiteness.
v2: Automatically increases screen brightness to max when opened, restores original brightness when closed.
v1: Initial release.