Any daredevils out there? This one is for you. The 'Almost Flying' achievement in Assassin's Creed: Revelations looks absolutely awesome to try. You'll have to parachute from the top of the Galata Tower (which I think is the highest point in the game), and fly all the way to the golden horn.
If you manage to accomplish this, have yourself 20G on Xbox 360, or a bronze trophy on PlayStation 3.