Vodka in a "gatorade ice" bottle. Used by eighth graders to get drunk in school. Whoever brings in the vodka is often suspended for the rest of the year.
Tyler: Uhhh. I'm sooo drunk.
Daniel: What's with him?
Bob: He was drinking Vincent's Eighth Graderade.
Gatorade mixed with liquor. Used not only by eighth graders, but by primary school drinkers everywhere, Eighth Graderade matches the strong but fast alcohol, typically vodka, with the sports athletic drink, Gatorade, which more suits the tastes of its 12-17 year old audience.
When properly mixed, Eighth Graderade looks exactly like Gatorade, and can thus be drank inconspicuously, even in school if the drinker is careful.
14 year old 1: Hey, you got any of that eighth graderade?
14 year old 2: Yeah, you want the vodka fruit punch or the lemon-lime tequila?