Now that I wrote it, somebody else might have done this before though...
Guns
A SOLDIER is in a BATTLEFIELD, firing his gun at the enemy.
The SOLDIER then looks through his binoculars. He sees an enemy soldier covered with green splodges of paint.
Puzzled, SOLDER takes his gun's cartridge out and forces out the ammunition from the cartridge. They are all green.
SOLDIER
Paintballs?! Where are the real bullets?
Cue to a PAINTBALL FIELD. There are a bunch of dead people in paintball armor lying on the ground, with real bullet wounds.
There are two corporate executives looking from a distance, in shock.
EXECUTIVE 1
This was your idea of a "team building exercise"?
EXECUTIVE 2
I didn't know!