Dear Fellas of Jackass,
I know the contest is over but an idea came to me in the shower that is so amazing that I think you should try it.
I call it: Air Sickness at 10,000 feet.
Start by having those who are going to do the stunt eat a good hearty meal of spaghetti (or something else that would really look gross when vomited).
Then as the plane takes off, have those who are going to skydive drink a bottle of ipecac (it usually works in a few minutes, so it would have to be tested and timed).
They then jump out of a plane litterally "hurling" toward the ground. They can even take a barf bag with them, which is probably not going to work.
Imagine all of the vomit falling in sync with the skydivers to the ground!
It's gross, crazy, and completely insane!