Several things have made me laugh out loud, but none more than these two:

"Am I about to discover where you, Ron, and Hermione disappeared to while you were supposed to be in the back room of Fred and George's shop?"
"How did you--"
"Harry, please. You're takling to the man who raised Fred and George."
p.134


There was a noise like a plunger being withdrawn from a blocked sink and Ron surfaced. Hermione acted as though she had not seen or heard anything.
p. 313