The potluck idea is excellent.
Here's a couple practical things to consider:
1. A timer. People can get crazy indecisive without a clock and an enforceable consequence for going over time.
2. Scheduled breaks. Setting up a few 5-10 minute breathers will keep it fresh. Those who like their last-second research can catch up, others will take their smoke break, get snacks, refresh drinks, etc.
These are only important to the extent that time and people's schedules are a concern.
As for fun extras, if you're looking to make an extended event out of it you could do something like:
1. Sports trivia challenge. You can usually find trivia board games for a few bucks at thrift shops and you don't need all the pieces, just the question cards.
2. Feats of strength.
3. Skills challenges. Bean bag accuracy toss. Football accuracy throw. Darts. Hatchet throw. Set up a milk crate and get some whiffle golf balls; have people try to chip into the crate (golf clubs are cheap at thrift shops, too).
Have people bring white elephant type stuff for prizes, or the previous year's champ can supply them. Homemade iron-on t-shirts make great prizes.
Of course, the draft is the focus. Don't overplan. Any extras just depends on how much time, space, and people you're dealing with.