Iron Chef for Teenagers: Ideas?

Our ward is having an Iron Chef competition for a combined young men/young women activity in a few weeks. I've honestly never seen more than fifteen or twenty minutes of the show, but have been doing a lot of reading up on it. It sounds like fun. How do I pull off a cooking competition for roughly 15-20 teen age boys and girls (mostly girls), especially on a very limited budget and in around 45 minutes? My biggest fear is that two or three will do all the work and the rest will wander the halls playing with their cell phones and ipods?

Any ideas for simple foods that will keep everyone interested and involved?

Here are a few that I've come up with. Maybe that will generate some ideas from all of you, too!

Set up a "grocery store" and give each person a set amount of money. Everyone has to buy something that will contribute to the meal.
Have some sort of secret ingredient like pineapple or potatoes (any other good ideas?) that everyone has to use in some way
Have each team make crepes: they get to choose the ingredients to make the fillings--one dinner crepe, one dessert crepe.
Have each team designate two head chefs, one girl and one guy. Do you think that would help the kids pay closer attention and keep themselves more occupied?

I went on a really fun date in high school where we had a cooking competition. We all went to the grocery store with $1 each. My team made stone soup (broth and veggies mostly) and had gummy peach rings for dessert. I think the other team made hotdog cut up in tomato soup or something.

I've been reading about hosting grown up iron chef dinner parties. I wonder if we'd end up with hot dog soup with a bunch of thirty something husbands making dinner.... (To his credit, my husband is an excellent and creative cook who loves to try new things. And he doesn't really like hot dogs any way. Grilled cheese is more his style.)