If you'd seen this ratty-looking NES cartridge at a yard sale, you'd be forgiven for not giving it a second glance. If you'd paid a few bucks to take it home, however, then congratulations: you just won the admiration of every gamer in the world. The 1990 Nintendo World Championship toured the US with a custom game that asked players to beat levels from Super Mario Bros., Rad Racer and Tetris in less than seven minutes. Just 116 of these carts were produced, each one going to finalists and competition winners -- making it one of the rarest Nintendo titles ever made. Now, this not-so-gorgeous-looking copy, where some misguided fool decided that scrawling "Mario" in ballpoint was an adequate replacement for the torn label, is available on eBay. The starting price is $5,000, less than half of the $11,500 someone paid for one in 2011, but you'd better hurry up and sell those organs, as the auction's due to finish in less than 48 hours.

[Image credit: mursean, eBay ]