Tetris is the most popular and profitable video game of all time. It is a puzzle game invented by Alexey Pazhitnov in 1985, while he was working for the Academy of Sciences in Moscow, Russia. Tetris was one of the first commercial enterprises to sneak out from behind the Iron Curtain to be marketed in the West. It has been proven to be highly addictive and appeals to more demographics than any game ever before.