How exactly would it work?
Staff of the Ancients
Modified for Tournament Play from a Pulp Campaign
Everybody brings one "good guy" team and one "bad guy" team of a "certain level". (dependent on the milieu/era and gaming system you pick)
Everybody plays an equal number skirmishes for each of their teams against different opponents (depending on # of players) to recover the "clues" (read: Victory Points) to the location of the components of the Lost Staff of the Ancients.
Players by highest scores are sorted into "good guy" and "bad guy" alignment. These teams play an even number of both sides of "assault/defend the lair" skirmishes against different players of the alignment side they are (good or bad) to steal/defend their clues.
Split players into two brackets: the highest scoring two (or three, for a big table) good and bad guy teams and the runner up bracket.
Each bracket plays a multi-way "recover the components" scenario in an exotic (and lethal) locale based on the clues they have won so far in a "winner takes all" final round for their own bracket.
It's basically Act I, Act II, and Act III of a stock-in-trade pulp multi-game campaign, distributed across teams.
The actual numbers and size/scope of scenarios would need to be fit for the number of players and time allowed.
