Fellow by the name of A.I. Bot created a really fascinating phpBB extension called phpBB Rivals. It's a clan/ladder/tournament (and coming soon, /league) extension that allows the creation of gaming clans with a tournament structure. Full tournament management, rankings, all that jazz.
Really great stuff for RPGs, online gaming leagues, dart tournaments, any community that involves tiered competition. And with a couple of mods to the language file, it can really be adjusted for just about anything, if you'd like to move the terminology away from online gaming.
As a punBB user, I asked the guy (who also makes a Vanilla port) if he was interested in making a punBB mod out of the extension. He said he'd be happy to consider it if there was a sizeable interest. He needs to prioritize his work according to demand, understandably, because it's quite popular in the forum software environments it's currently developed for.
So he suggested I put up a post to poke about and see if the interest exists. All I'd ask is that if you're interested you reply back with a quick "Hell yeah" plus any lols, roxors, or rotfls you'd like to toss in. That way I can hopefully show him the discussion as proof that the interest exists, and convince him to set about creating a mod for our light 'n lovely forum baby.