Drink when . . .
You can see the script.
Someone stumbles or almost forgets a line, but keeps going anyway.
There's mocking.
Keith emotes.
Someone is eating something they REALLY don't want to be eating.
Megan kicks, hits, punches, or otherwise abuses someone. Twice if it's Lindsay.
Someone dies. Twice if it's Lindsay.
A hat and no other costume change denotes a different character.
Addy is onscreen.
There's an in-joke.
There's Spam.
Chekov "moves" by himself.
Chekov plays a character other than himself.
We're ad-libbing.
Something or someone that isn't supposed to be in the shot...is.
You see Clarence.
You detect something lifted from Monty Python.
Someone, as a result of playing two different characters, talks to themself.
There's an announcer. Twice if it's the stick-slapping news announcer.
You see the shawl Katie's mom wore to her junior prom, and say "Isn't that the shawl Katie's mom wore to her junior prom?"
There's a cop. Twice if it's Lindsay.
There's a crazy person. Twice if it's Keith.
You see "the crew."
Claire fights and it looks really fake.
There are mysterious hair changes from scene to scene. Twice if it's Claire. Finish your drink if Claire's hair reverts back to its original state in the next scene.
You can see that someone is not wearing any shoes when she should be. Twice if it's Katie.
You can see that Lindsay is wearing the black Nike basketball shoes.