Thieves Guilds.
COMMANDOES (be they in space too).
King vs King (their kingdoms are presented elsewhere and people give their roleplays attention, respect, and reknown. Those individuals for Baronies, Estates, Duchies, Kingdoms and/or if need be an Overlords fief do an ultimate gladiator duel. They don't need to be in gladiator gear, what they normally wear works too. Whether to the death or to an induction to ones other kingdom by sworn-shield/sword and role-played from there would be rather nice.).
Animal Riders (be they tribal, barbarian, or noble. No mythical animals... let's not get ninja there.).
Perhaps a race of some sort like MotoGP.
Dinosaur Hunting.
And maybe an Amazonian vs Rambo thing.