It's perhaps the most iconic game on this list, and one that you can never win — those blocks fall faster and faster until you end up merely shunting them desperately from side to side, in the hope of holding out just. . .a. . .little. . .longer. This means that the challenge is never over — all you can do is try one more time to beat your high score, or your friend's high score, or the high score of some random person on the Internet. Designed by a Soviet engineer in the 1980s, Tetris has jokingly been accused of originally being a Cold-War secret weapon of mass distraction. Given the addictive nature of the game, let's just say it's a very compelling theory.