Snake games come in a wide variety of forms and formats but the basic idea is usually the same. Starting off in arcades back in the 1970's the concept has spawned hundreds of versions.
Snake involves directing your initially small snake to eat blocks on the screen, as you do the length of your snake increases. This makes the game more difficult as you lose if you touch the side of the playing area.
The other main variant on the game is where you have several snakes or player on the screen at once and each tries to block the other's path. This can be seen in games like Curve, Curve 2 and was even brought to the big screen in the movie Tron.