Storm Trooper Practical Jokes
Replace Darth's lightsaber with a flashlight.
Switch Vader's oxygen supply with helium, first one to laugh, dies.
Blame the new admiral for making the mistake that cost you the battle.
Tell the tall guy "yeah, the blast door's open all the way".
Rewire hangar speaker system so it plays LaCucaracha when the Emperor arrives.
Tell the new guy that Darth appreciates constructive criticism.
Convince rookie pilots that TIE Fighters have shields.
Switching uniforms and seeing if the commander can tell the difference.
Sneak up on daydreaming guards and breathe through a can.
Stick "I got your Force right HERE" signs on Executor bridge crew's backs.