The moment in the pilot that shows off Ben's Butt Monkey status - he wakes up with no clothes, has to wear a women's silky bathrobe, goes out and bumps into the Carnivale's Giant, is knocked into a puddle of mud and horseshit, and to top it all off, Jonesy makes kissy faces and mocks him in front of everyone.
Justin and Iris's hilariously pedantic and cliched argument in "After the Ball is Over" - Justin's still fixated on both his weird dreams and perving on his sister in the shower and Iris calls him out on not hearing a word she's just said. His stammered response consists of "is that a new dress?"
The "Fireball Show" in "Insomnia" where Stumpy successfully shows the crowd a Man Eating Chicken. The reactions on the crowd are just priceless
Ruthie's freakout when she sees Stroud kidnap Scudder and she thinks she's still seeing ghosts.
"They have cars!"
The lengths the carnies go to in order to invent shows can be pretty funny. Further, Stumpy's sales pitch for every cootch show is based on hyping the event by exaggerating it, while going by whatever theme is on that night. Some of the things Stumpy slaps together are pretty chuckle-worthy.