It looks like there aren't too many sports game fans on The Escapist. I think a tournament with Madden is a great idea.
I used to be the head of gaming for a failed convention. I wanted some sports titles but everybody else thought that sports fans mixing with cosplayers and anime fans was a recipe for disaster.
The one thing that decided whether or not to put a game in the con was local LAN. It would be great to system link two consoles using a crossover cable but that no longer appears possible. Back in the day we had to bring our own switches, one for PS2 (six systems), the other Xbox (12 systems). It looks like Madden '12 isn't even system-link compatible. That's too bad as two local competitors with their own screen makes for a great show. The great part about splitting the crowd is that it's almost like a real game.
Until you can further research it, I say stick with the basics of having any stranger use your system. Keep a close eye on your controllers. Set the rules up prior to starting, like no controller rage. Keep your system safe from accidental kicking and drink spills. If it's on 360, consider bringing the battery case and extra AA's. That or extra play-and-charge cables or mini USB for the PS3. Might want to go wired and use USB extension cables from the console itself--a homemade 'breakaway' cable.
-Edit- Oh right, and controllers never seem the same after a dozen frantic players use them. Might just be a mental thing, but we had quite a few controller failures after the first con.
I've never played a sports game, so I would have to start playing it immediately to familiarize myself. Check for the local split screen option (which would save a lot of time) and try to find out if you can change settings on game types; e.g. custom game time limits and being able to dictate which player gets the top, which on the bottom. If that can be set, you can have a coin toss before each match to see who gets what.
Good luck man!
