Snake

Snake is a Top Down View Maze Game, with a twist; you not only navigate the maze, you are the maze. You play a snake, slithering around in a pit eating food. Every time you eat, you score some points, and you get longer. Eventually, you get so long that you have to navigate around yourself. The game ends when you crash into yourself or a wall.

Based on an arcade game from 1976 called Blockade. First appeared in its present form in the late 1970s on the TRS-80, Commodore PET, and Apple II. Multi Platform in the extreme, because both the program and the graphics are so simple. In 1997 it became the first Mobile Phone Game when it appeared on Nokia phones.

There's also "Mu-cade" - a Snake/Centipede hybrid shmup for OpenGL by ABA Games (as FLOSS, available in many Linux repositories).

Snake provides examples of:

 * Endless Game: You slither around until you crash into yourself or a wall.
 * Follow the Leader: The Light Cycles game from Tron is based on Snake.
 * Freeware Game: Plenty of free versions out there.
 * The Golden Age of Video Games: And every age since.
 * Maze Game
 * Multi Platform: Ported to just about every platform in existence.
 * No Plot, No Problem
 * Scoring Points
 * Top Down View
 * Wrap Around: Some versions let you do this, in which case, there is no wall (unless you count yourself).