The entire "Homerpalooza" episode of The Simpsons, my nominee for funniest episode of any TV show ever.

TEENAGE HOMER: You wouldn't understand, Dad. You're not with it.

GRANDPA SIMPSON: I used to be "with it." But then they changed what "it" was. Now what I'm with isn't "it," and what's "it" seems weird and scary to me. It'll happen to you!

also..

(while driving Bart and Lisa to school)

HOMER: "Well, we'll have to organize a carpool. Hey! Every day will be like a road trip! With your dad! To school! So how about those rainbow suspenders, huh? Pretty cool way to keep your pants up, eh? I see these kids now with jive printed on their shirts. Now, I can teach you how you're supposed to say jive. "You jive turkey!" See? You got to sass it. "Quit jivin' me, turkey!" You got to sass it. A turkey is a bad person."

and of course...

BILLY CORGAN: "Hey, Cannonball. I like your statement. When life takes a cheap shot at you, you stand your ground. Billy Corgan, Smashing Pumpkins."

HOMER: "Homer Simpson, smiling politely."