Tux Racer

Tux Racer is a Free Software 3D computer game starring the Linux mascot, Tux the penguin. In the game, the player controls Tux (or one of three other characters) as he slides down a course of snow and ice collecting herring. Sliding on ice makes Tux go faster, while sliding on snow allows for more maneuverability and sliding on rocky patches will slow Tux down. There are also trees to block Tux's path and flags for the sake of marking out the course. Source: Wikipedia, "Tux Racer", available under the CC-BY-SA License.