From the game Perfect Dark for the Nintendo 64.
You can jump off the top of a 20-something story building in the first mission, Agent mode. Get the door so it opens from the inside (like it's facing towards the outside). Jump off the helipad and land on the door, crouch, and you can fit through the wall. Free fall for a bit... and you may just end up at the end of the level, taking only six seconds!
Submitted by: Axem Snow and AndyDark