Well i screwed that right up didn't I. Proper Article is here http://www.cracked.com/funny-2708-the-tetris-effect/ This will be deleted...as soon as i figure out how.
The Tetris Effect first was noticed, studied and later named, for the game Super Mario Brothers.
Only joking, it was Tetris. Dumbass.
The Tetris Effect is actually closely related to Earworms. Earworms are not, in fact, worms at all. It is just a highly nightmarish term used by, presumably bored and sadistic, scientists to describe having a song stuck in your head.
These scientists went apeshit over it, namely because they had found an excuse to play Tetris at work. Seriously though it turns out that longterm play of the game is good for you. Not to go into too much detail but, in basic terms, it kills off lazy brain pixies, making your brain consist only of the faster ones. This only applies to the brain pixies that help you to play Tetris though. This does include your basic spacial awareness and your ability to see and decipher patterns, as well as your ability to work at high speeds without succumbing to pressure related stress, so it's actually a lot more helpful than it sounds.
Unless you like your lazy brain pixies of course.
The Tetris Effect, despite its name, isn't limited strictly to Tetris or even gaming as a whole.
Prolonged play of any game will result in your brain going equally mushy. Too much Animal Crossing and you may find yourself thinking about things in terms of visualising the inventory. Even more Animal Crossing results in posting fish through your neighbours door so that they'll get you a NES for Christmas. Not really but you get the idea.
Other dull and tedious pastimes that induce the effect include chess, cards, driving long distances, flipping burgers, stacking shelves or picking weeds. Reports of poeple suffering second degree Tetris Effect from Animal Crossing induced weed picking are, so far, unsubstantiated.