The Xbox 360 version of Triumph Studios' Overlord is soon to receive an update to multiplayer - namely, split-screen support.
The update is free, and all existing multiplayer maps will support split-screen. As yet there's no confirmation on when the update will release to Xbox Live Marketplace, nor how many players split-screen mode will actually support.
Overlord is kind of like Pikmin meets Fable meets Dungeon Keeper, with you the player assuming the role of Overlord and attempting to conquer a fantasy world. Helping the Overlord out are minions under your control that you can use to do the likes of attack enemies, push obstructions out the way and even boost your health by sacrificing the little blighters on an altar.
You can read a review of the Xbox 360 version here.