Now I really wish we had recorded the one we did on April Fools.
A friend of mine is a manager at the local McD's. So we set up an elaborate prank (he knew about it, his employees didn't).
The first friend drove through the drive through like normal. I was walking behind the car and we had a third friend behind me in a car (Blocking any possible traffic interference). After the first guy ordered, I tried to order. Our McD's has a strict 'No Walk-Ups' policy, so the guy taking the order wouldn't serve me. After the first guy got his food, he started to pull off and I ran up and pretended to steal his car (GTA style, threw him out away from the car and backed it up to the menu board). I yelled 'You gonna take my order now [explictive]?' The guy kind of freaked out and started yelling for the manager (Our friend, in on the joke) to call the cops. He pretended to, and we continued messing with the people. After he wouldn't serve me, I parked the car, went inside and started yelling and making a scene.
After a couple minutes I demanded to see his manager (the friend), who came out yelling and stuff at me (He's normally really quiet). After a few minutes of that (and everyone starting at us), I ended it with 'Oh yeah? Well I'm going to call your Corporate Office and tell them what a freaking awesome April Fool's joke we just played on everyone!'.
...Sadly enough, because we were at a McDonald's, some of the people still didn't get it
What's also fun is to sit next to the ordering box and comment on people's orders. "Can I get that with no mustard?" Me: No mustard? Come on, mustard is awesome! If anything hold the mayo. Do you know what that is? It's pure fat, going straight to your hips lady!