Clyde is one of the South Park elementary school students and has given several last names on the show: Goodman, Harris and Donovan.  We're gonna go with the last one as our official choice.

Clyde Quotes

Clyde: Hey what's going on?
Kyle: Tweek and Craig are gonna fight!
Clyde: Really? CoolIt's funny because Tweek and Craig both went home about 15 minutes ago.
Kyle: What?
Token: Yea, they left.

Mr. Mackey: Wh-wh-what you need to do, uh, Damien is...is to be overly nice. See, n-no matter how mean the other kids are to you, just don't retaliate. Err, be passive, mmm'kay? That's what I taught the little British boy, Pip, an-and just look at how much the other children like him now!
(scene changes to the playground, a group of kids are gathered around Pip)
Clyde: I bet I could spit the most on him! (spits on his left shoulder
Bebe: Oh, yeah? I bet I could spit in his hair! (spits in his right eye)
Pip: Oh! Nice try! A little higher and you've got it!

South Park Quotes

Mr. Garrison Sr.: Would you have sex with your son to save his life?
Man at bar 1: Oh, this is one of them scruples questions ain't it?
Man at bar 2: No, no I got a better one: Would you have sex with your motherto save your father's life?
Man at bar 1: You mean like if someone had a gun to your father's head and said if you don't have sex with her, I'll kill him?
Bartender: If a killer put a knife to my throat and said "have sex with your mother or I'm gonna kill your father while having sex with you, I would have sex with myself.

Mr. Garrison: Who knows what a can food drive is?
Cartman: Isn't that where they cut open a chick's stomach to get the baby out?
Mr. Garrison: No, that's a caesarian section, Eric, but remember there are no stupid questions, just stupid people.