Joke #1:
(Harry Potter is sleeping in bed when a dementor comes through the window)
Dementor: (tickles Harry)
Harry Potter: (wakes up and puts glasses on) Expecto Patronum!
Dementor: (dodges patronus)
Harry Potter: Can't a man sleep in peace?
Joke #2
(Crookshanks is sleeping on a bench when there is loud barking)
Crookshanks: Reeeow! (Runs away)
Hermione: (to dog) Heel!
Dog: (heels)
Hermione: (checks for dog tags) Well, I guess I'll feed you. Stay!
(Hermione exits and returns five minutes later with fresh ham to find Sirius in place of the dog!)
Hermione: Sirius!
Sirius Black: Hey, a man's got to have a little fun!
Joke #3
Ron: (hands Fred a present) Here, Fred.
Fred: (opens present) Hey, this baseball cap says George!
Ron: (guilty) Oops, wrong present.