Tetris was invented by Russian Alexey Pajitnov when he was working for the Soviet Academy of Sciences. He was supposedly bored at work and created it to pass the time.
He and his friend tried to sell it but couldn't get it to sell, so they gave away some of the copies to friends. This created a chain reaction that made it a phenomenon.
With such an odd start, it's no wonder that the copyright situation was a bit of a mess.
The NES version of the game, for example, is technically pirated, making it one of only a few pirated games to be sold on store shelves. There were many other issues regarding the copyright as well.
One of the most interesting parts of the rights to the game was the fact that Pajitnov, the game's creator, didn't receive any money from royalties for over ten years because he technically didn't own the rights.
Ironically, today you can play the iconic game free online. It's officially sold 170 million copies, but with piracy, knock-offs, and imitations, the total number of copies sold, the number could easily be twice that.
