DB Cooper is that guy who hijacked a plane and then received $200,000 in cash to release the hostages. He also required that the airplane be flown to Mexico which, surprisingly, the neogiators agreed to . As the plane flew to Mexico, he opened the rear hatch and jumped out with a parachute. No one has ever found out what happened to him. Some people think he died in the jump while others think that he survived and is living off of the cash somewhere.
According to a story from the AP (via Yahoo!), a parachute was recently found in Washington state that may have been the one used. It is unclear if it is his parachute or not and they are still analyzing, but it is interesting that some evidence from this very old case is emerging. Perhaps it will finally put the basic question to rest about whether he survived the jump or not.