In singleplayer, go to Setup -> Game Rules and change the "matchframes" setting to change the length of the match, and the "turnframes" setting to change the length of each turn.
In multiplayer, you'll probably have to use server commands.
"Call yourself alive? I promise you you'll be deafened by dust falling on the furniture,
you'll feel your eyebrows turning to two gashes, and your shoulder blades will ache for want of wings."