Treasure Master is a video game released by American Softworks in 1991 for the Nintendo Entertainment System as part of a contest involving MTV.
The Contest
After the game's release in late 1991, players had until noon EST on April 11, 1992 to practice beating the game. At this time, MTV revealed a secret password. By entering in this password and the game's serial number before beginning the game, players unlocked a secret sixth "Prize World" level. After this, players had until midnight to complete the entire game including the Prize World. This prompted the game to reveal a 24 character code. By calling in to a special hotline with this code, players had a chance at winning one of 36,252 prizes.
Secret Password
The password to play the full game is: 3HDJL9DNQV2WYTV4S91RXR86
Source: Wikipedia, "Treasure Master", available under the CC-BY-SA License.