ROCKET JUMP

Origin
Rocket jumping was first introduced in the Quake series, but made popular in most VALVe video games, (i.e Team fortress 2, half life 1-2) although in Half Life 1, it was used by the Super-charged "Tau-cannon."

Variations
There are many variations of rocket jumping, such as Sticky-bomb Launching, (TF2) GravityGun Flinging, (HL2) and Tau Launching. (HL1 games) More variations include the Left 4 Dead grenade launcher exploit, in which you can launch your friend into the air to get out of the map.

History
The Rocket Jump was used more of a game exploit, or a cheat for use for the player's advantage. when Team Fortress 2 was released in 2007, VALVe supported the rocket jump as a way to get around the maps and to avoid enemy fire in-game, which is ironic because you get injured yourself.

How to Rocket jump
One must play with a rocket launcher or with a class with a rocket launcher (or anything explosive) and must simultaneously jump while shooting or detonating the explosive, pushing the player in any direction from the force of the explosion.