Sometimes during NBA games a team will run a promotion that allows fans to shoot a half court shot, or shoot free throws, or maybe 3-pointers.  At this Mavericks playoff game in Dallas against the Golden State Warriors, they let a fan take a crack at dunking a ball while launching himself off a trampoline.  Check out the video below to see the rim-shaking two-handed jam that this fan threw down.  It's beyond description.