So, two guys go to the Attic Bar on the 48th floor of a London skyscraper, have a couple of beers, go to the bathroom to get their equipment on, then walk through the bar to the outside balcony, and jump off.  Insane but true.  According to the YouTube description, they had been planning this stunt for a few years, and they were at the bar that night until last call.  They had to wait until then to jump because the wind speed had been too high.  They got lucky and at last call the wind speed had died down enough to base jump off of the balcony.  They were never arrested, and the bar says they had nothing to do with it.  Absolutely crazy, but made a great video.