Having just thrown a food fight myself, I've collected a list of tips and tricks.
Good Foods to Throw
pudding (pistachio was great)
I chose neutral-colored foods because they're cheap and they don't stain. If you want to get dirtier, here's a list of more suggestions.
Good Foods to Throw That Stain
If you want colored popcorn, here's a good recipe.
Pie tins and plastic bowls aid in carrying/throwing food.
Water balloons and water guns filled with milk or kool-aid give you the advantage of distance.
Flour is the prettiest of all the throwing foods.
Set ground rules.
Take it slow with young kids. They may get overwhelmed quickly.
Call time outs.
Cooking the spaghetti al dente is best, because fully cooked spaghetti sticks to floors like no other.
Have basins of water available for the participants to clean their feet off before walking anywhere else.
Don't use towels for clean-up. They don't do well in the washer or dryer. If you do use towels, rinse them off in a sink with a garbage disposal before putting them in the wash.
If you use a mop, be prepared to throw it away afterwards.
Putting painter's plastic down on the floor helps contain cleanup.
A food fight would be easiest to clean up if it's thrown outside, but make sure you stay on your own property--no public parks.
Make sure to have a change of clothes available.
If using a cement floor, such as a garage or warehouse, buy one of those long squeegees to push all the thrown food to one side of the floor.
Try to remove all popcorn kernels before throwing begins, because they're harder to find in the cleanup.
Here are some of the fun photos captured at our food fight photo shoot.