Spidey: I don't suppose I could convince you to come up here and fight like a spider?
Peter's exasperated reaction to the Punisher figuring out he's really... the Green Goblin. It comes to a head when the Goblin himself shows up. "Well, whadday know! That must be ME up there!"
...and everyone else
Alicia: "Well, at least I won't be changing diapers anymore..." Silvermane (re-aged to geriatric level): "I wouldn't be so sure!"
I don't know about anyone else, but this Troper dies laughing every time baby!Silvermane ever opens his mouth. Just hearing a little kid's voice saying things like "Bah! My mind is trapped!" is hilarious.
Tombstone observing the fight between Spider-Man and Smythe's Mega-Slayer:
"Only problem here is, I don't know who to root for."
An alternate reality's Gwen Stacy explaining that she recognized Spider-Carnage as the impostor because he's "as nutty as a fruitcake."
The Kingpin helping save Peter's wedding by completely owning Scorpion with the Mega-Slayer:
Kingpin: Gargan, your corrosives have no effect on this robot! Scorpion: Oh yeah? How about this! [Scorpion swings his tail, but the Mega-Slayer grabs it] Kingpin: YOU FIGURE IT OUT! [the Mega-Slayer swings Scorpion around until his tail snaps, sending him flying] Kingpin: I broke him? A pity. I was just starting to have fun!
A loopy Harry Osbourne singing, "Spider-Man and the Punisher, sitting in a tree! MJ, MJ, MJ and me!"