Nintendo World Championships 1990 is a special game that was used in the original 1990 Nintendo World Championships where competitors had to compete to be the best at Super Mario Bros., Rad Racer, and Tetris. After the event ended, participants were given a gray NWC 1990 cart (90 were made in all) and for Nintendo Power subscribers, a special gold cart was made available to 26 lucky Nintendo Power subscribers. Due to the low amount of carts made, this made NWC 1990 a highly sought-after collectors' item and the rarity made sure sell prices remained high in that you probably had to pay an arm and a leg and give up your first born child to be even be able to snag one.
If you want to see highlights of the event:
If you want to see the game running:
NWC 1990 would be the last time Nintendo held a world competition until 2015. NWC would even be referenced in the NES Remix games where you could play a special set of challenges from Super Mario Bros., Super Mario Bros. 3, and Dr. Mario in NES Remix 2. The NWC 1990 would even be given a homage in the movie The Wizard where the competition at the end was NWC-styled (and gave viewers an advanced look at Super Mario Bros. 3 before it released).
Now to the main point of this thread (besides discussion):
Bootleg copies of NWC 1990 are starting to be circulated. If you're looking to snag one of the 90 original copies or one of the 26 gold copies, you now have a bigger headache in bootleg copies besides the money woes.