"Tell me, Harry, what evil could you accomplish if a Dementor were allowed onto the grounds of Hogwarts?" ... "Gur Qrzragbe vf n qvfgenpgvba," Harry said.

I spotted this one right away because it matched a certain pattern of thought that I use relatively often. Rirel gvzr V'z qevivat va n gvtug fcbg naq gelvat gb nibvq uvggvat fbzrguvat ynetr naq fnyvrag, V znxr fher gb nfx zlfrys: Nz V cnlvat fb zhpu nggragvba gb gur ovt guvat gung gurer fbzrguvat ryfr gb juvpu V'z abg cnlvat fhssvpvrag nggragvba?