While Stadium Events remains the most expensive and rarest officially released NES game, the holy grail of collecting is hands-down the Nintendo World Championship cartridge. It was produced in two versions, gray and the rarer gold versions. 

·      The 1990 Nintendo World Championships ran across 29 cities and was based on competitors scoring the highest in Super Mario Bros., Rad Racer and Tetris within a time limit of 6 minutes and 21 seconds. The three games were put on the 100+  Grey version NWC carts designed specifically for the contest, some of which were awarded to finalists.

 ·      Only 26 Gold carts were made for the Nintendo Power Magazine NWC giveaway and currently less than 20 are confirmed to exist.

  ·      This is the most valuable and one of the rarest video games of all. The last copy sold privately for 6 figures.