Randal "Randy" Marsh is Stan's father and as a geologist he's surprisingly involved in a lot of the plotlines in South Park.   Randy has also been revealed to have a decent singing voice, having been involved in a boy band as a kid, and knows how to play the guitar.

Randy Marsh Quotes

Randy: How does it feel to be a hundred and two, Paps?
Grandpa: Shoot me!
Sharon: Make a wish, Grandpa...
Grandpa: I wish I were dead!
Randy: That's our silly Grandpa!
Grandpa: I'm not kidding, God Dammit! I really want to die!

Randy Marsh: I think I'm getting that stomach flu you gave me.
Mr. Garrison: It's that little Kenny bastard that gave it to me.
(the mayor exits the porta-potty)
Randy: Hey, mayor. Were you making gravy in there?
Mayor: I just gave birth to a brown baby boy.

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.