Low country boil is where you get big pots and boil: shrimp, sausage, corn, potatoes and crab boil all in the same pot, and then you can add other stuff like crabs, crawfish, onions, carrots, whatever else that's similar to stuff already in it that you want. There's a recipe for a small batch of simple low country boil here:
http://www.coastalliving.com/coastal...609731,00.html
And for events someone else can provide better ideas since we don't really do events, but my one caution would be if you're looking to make it a little more fun, make sure the focus stays primarily on conversation or you'll end up with worse problems pledging kids you didn't want because people are voting on bids without having really met the kid.
I guess low country boil may be more of a coastal GA/Carolinas thing and wouldn't be as big of a draw if not that many rushees know what it is, but it is delicious and will draw in a lot of rushees if people are familiar with it in your area.