(n) 1. a band that used to be good but was taken over by middle schoolers, 9th grade girls, and fake-ass emo chicks.
2. a day where you smoke weed and drink booze; also called 420
1. Green Day is an example of, well, a Green Day band.
2. Stoner: Wow, look at me, I smoke weed, I'm cool, it's a green day.
Some dude: You mean, like the band.
Stoner: Uh, no...wait, what?
Some dude: Didn't you just mention the band Green Day?
Stoner: Oh, you mean the "I walk this empty street on the boulevard of cocks" guys.
Some dude: Yeah
(Stoner pulls out shotgun for no apparent reason and blows dude away, because thats always what happens at the end of these gay dialogue thingys)