As title.
For me it would be Island Troll Tribes, a custom map for Warcraft III: The Frozen Throne. It is a team survival map where the object is to eventually defeat the other tribes through skills/teamwork. There are three stats each player needs to keep track of - health/hunger, energy/fatigue, and heat. Alchemy-like recipes are used to make everything from tools to buildings. had a lot of fun with it
Another good WC3 one was Dark Deeds - a stronghold builder type map where one player was randomly chosen to be evil, given supernatural powers, and set to work against the other players. The others would have to uncover the villain before he destroyed/recruited the rest. there was a lot of paranoia and trickery in this