I think a pretty decent idea that has not ever been thought of is a drifting event in Forza 4. 32 entrants, 2 per match, compete to get the highest score on a track. The person with the highest score wins the round and advances to the next, just like a normal tournament. Single elimination, we'd have to work out a couple kinks, such as referees and what not. But I think this is a unique yet brilliant idea that might not have ever been brought up for KSI's Spirit Week.
Who's with me on this? lol