If you stop and think about it, Tetris is less a puzzle game, and more a simulator that has players building virtual forts using randomly-shaped couch cushions. Except that in real life they don't disappear when you've completed a layer, nor do these giant Tetris cushions that finally fulfill the game's true living room couch fort destiny.
A set of five shapes—also known as tetrominos—will set you back $100 from ThinkGeek. But you'll need a lot more than just five to defend your living room against invaders, so it's probably a good idea to order a bunch of sets before you start building your fort. As an added bonus, it also means you'll have a safe place to hide once your partner sees your credit card bill at the end of the month. [ThinkGeek]