Thanks all for the suggestions. We've done many of these incarnations in the past couple of years, but there are always tweaks to be made to keep it fresh. Looks like we're leaning towards a Food and Beer pairing comp where the food contribution must be made with some of the home brew.
FYI: One that we have made an annual event for our December Holiday Party is a Secret Santa. Everyone involved must give a style and one additional ingredient that must be used by their chosen recipient. The brewer has some latitude in using the special ingredient. For example, last year I was given a Foreign Extra Stout and a can of Cranberry sauce. I didn't have to use the sauce, it just had to be cranberry-something. I brewed the stout and then racked onto muddled whole cranberries. What I learned is that I should have added cranberry juice instead. The combination of the roasted grains and just cranberries ended up being too tannic.