For me, it was the game Rocket Jockey released by Sega Soft in '96. It was perfect. The game featured a surf rock soundtrack by Dick Dale. The entire premise of the game was to ride around on rockets and using long cables to yank your opponents off theirs. Referees were also fair play. I don't think I've met anyone else who has played the game, so if you have, let me know!
Releasing the T. rex and plopping guests into the shark tank and removing the ladder were important parts of a successful zoo. I wish the Zoo Tycoon series kept the same level of freedom the original has, the new one was depressing to play.