How would you like to earn a quick 15 bucks and be part of some very peculiar research? It's easy. First, put on a padded flight suit, strap on a helmet, wrap your neck in a cervical collar, and pad your buttocks and lower back. Next, get into a parachute harness and hook yourself to an overhead cable track. Ready? Comfortable? Now, walk up and down a flight of stairs and, when you least expect it, you will trip an infrared sensoring device that will collapse the entire stairway out from under you. You take the big fall. If you're afraid you'd look silly, we should