An Idea for a Gametype:

Just a thought that passed my mind just now:

Imagine a 4v4 on Twisted Treeline with no active turrets, no shrines, and no minions, the lanes and center jungle becomes a pure, champion fighting ground. The catch: instead of a nexus, each team has an allied Baron in their respective base (in the location of the nexus - the spawn fountain is unaffected). If you kill the enemy's baron, you win - you just have to fight in the center long enough to be fed, and know when it's appropriate to attempt such a challenge. The rounds wouldn't be stupendously long, of course (most likely 20 minutes or less), but it's an interesting dynamic to think about.

Edit: The barons have their standard health regen - meaning you need to kill it like you normally would - without the ability of coming back later to finish the job. It's an odd difficulty curve, but one that might compel unique gameplay and strategy.