The sole greatest Legend of Zelda game in existence, and therefore the greatest video game in existence as well.
Developed for the Nintendo 64 and released on November 23, 1998, this was the first time we saw a 3D Zelda game. It won the 1999 Game of the Year award. It has held the #1 spot on GameRankings.com for over a decade.
Preorders of the game were received with a gold cartridge, whereas off-the-shelf versions were received with the standard gray carts seen on most N64 titles. The two styles of carts bear few differences in gameplay, only in the changing of Ganondorf's blood from red to green, the removal of an Islamic chant from the Fire Temple's background music, as well as the fixing of a few reported glitches in gameplay.
Ocarina of Time spawned a single direct sequel, Majora's Mask in 2000, which takes place after Ocarina of Time's child timeline. This would be the last time we would see a realistic style Zelda game until Twilight Princess in 2006.
Ocarina of Time has been subsequently re-released on the GameCube on a promotional disc for preordering WindWaker, as well as on a Collector's disc featuring The Legend of Zelda, Adventure of Link, and Majora's Mask that was bundled with new GameCubes. It has also been released on the Wii's Virtual Console, retaining all but its rumble ability. These versions are based on the gray cart versions of the game.
Ocarina of Time has set a new standard for adventure games that has yet to be topped.
There aren't enough words in any language to describe how awesome Ocarina of Time is.