When the kids are going door to door and getting their bags filled, you can actually see the rocks being tossed into Charlie Brown's bag.
When Lucy goes bobbing for apples and comes up with one that has Snoopy on the other side and freaks out.
Blecch! My lips touched dog-lips!
When Schroeder plays "It's a Long Way to Tipperary", "There's a Long Long Trail" and "Pack Up Your Troubles" in succession, and Snoopy's responding mood shifts from happy to sad accordingly...
Culminating when Schroeder's rendition of "Roses of Picardy" provokes an "OwwwOOOOOOOoooooooOOOOhhhhhhhhh!" from Snoopy.
Snoopy rising out of the pumpkin patch and causing Linus to faint; then disappearing immediately after.
When the Great Pumpkin fails to appear, Sally gives Linus an epic dressing-down that culminates in her violently shaking him while hollering "YOU OWE ME RESTITUTION!"
Charlie Brown trying to console Linus:
Well, don't take it too hard, Linus. I've done a lot of stupid things in my life, too!
He had inadvertently pushed Linus' Berserk Button when he said that. Linus proceeds to berate him all through the credits.
Charlie Brown being forced to be a model.
...for a jack-o-lantern.
A brief visual gag with Lucy holding a copy of TV Guide with her own picture on it.
When Snoopy first sees Linus writing to the Great Pumpkin, the beagle starts laughing hysterically. He walks over to Lucy while laughing...who promptly tosses him away like a rag doll.
In the beginning, Linus, eating a huge sucker & is sticky as all get out, jumps in Charlie Brown's leaf pile & ends up with a leaf-covered confection & an adorkable "beard" of leaves. Quoth the leaf-bearded Van Pelt boy, "Never jump into a leaf pile with a wet sucker!"
This promo for a 2003 Canadian airing of the special.