Map: Gridlock

Location: On both sides of the Boomshot spawn is a set of 2 cars.
You will need to be on the side with the 2 severely damaged cars.
Go on the bumper of the car next to van. Walk up to and stand right against the bumper in the middle facing the sniper spawn.
While pushing forward press A and B at the same time.
From there, if done right, you will be crouched in mid-air.
Press A and start walking on top of the 2 cars.

P.S. Use it to mess with the people on your team.