It's a rare moment when Kenny eats a school lunch like the other boys do. Here it's pepperoni pizza and a small carton of milk.
Blooper: when Kyle turns around and sees Cartman at his bedroom door, he's hanging off the back of his computer chair. Come to think of it, he's hanging off the back of it before Cartman comes in, too. Side views of Kyle in the chair do have him seated properly.
"You don't know 'cause you've never had a girlfriend, Kyle!" - Cartman forgot that Kyle did have Rebecca, the home-schooled girl who got aroused with one kiss from him and went off kissing every guy at the dance.
"Sorry folks, sorry." - Yates could indeed be breaking the 4th wall here, or he could just be apologizing to the rest of the office.
We're reminded that Sgt. Yates does double duty as a detective.
Garrison is wearing his glasses again.
"Mommy! Daddy!" The girl who says this ends up with only her mom.
Literary reference: The Crucible
Wang Chung - Everybody Have Fun Tonight