This is a video from the JesterLads at King's College London where a Jedi appears to make the doors to an elevator repeatedly reopen when they're closing. The prank works by having another person hiding outside the elevator secretly push the call button every time the dude inside makes a Jedi hand swipe. Not bad, but the best elevator prank is still jumping up and down as hard as you can and yelling 'I HOPE THIS THING F***ING PLUMMETS!'
Hit the jump for the video.
Thanks to Rob, who informed me the 'put headphones in and pretend like you don't know you're farting' is another classic.