The Janitor : Hey! We solved your dumb game.

Troy : We been to the libary!

The Janitor : -brary... Troy! Library! Anyway, what two coins, when you put 'em together, make 30 cents and one of them isn't a nickel? Uhm... A penny and a 1972 dime with a Roosevelt imperfection, today worth exactly 29 cents.

Dr. John 'J.D.' Dorian : No, no no. The correct answer is a quarter and a nickel.

The Janitor : Uhm, no, because you said one of them isn't a nickel.

Dr. John 'J.D.' Dorian : Right. The other one is.

The Janitor : You lied to me.

Dr. John 'J.D.' Dorian : No. It's a riddle.

[leaves] 

Troy : [to the Janitor]  Uh, your face is red like a strawberry!

The Janitor : ...Don't have kids.