These i found places, but i thought they were funny so hope you enjoy :D
WAYS TO ANNOY HARRY POTTER

- Ask him to tell Cedric you said hello.

- Follow him around and say "Voldemort is your uncle!" in a loud voice right next to his ear.

- Ask him if the "anvil-sized hints" ever hit him on the head, which is really what caused the scar.

- "So... first you were the Boy Who Lived.. then you were a nutcase... now you're The Chosen One. Why don't they just add it together so that you're the "Chosen Nutcase Who Lived?"

- Offer him stolen silver from Sirius Black's house.

- Make sure you tell him you got it from Mundungus Fletcher.

- Tell him that he should stop pretending to be Harry Potter and to wipe the fake scar off his head.

- Follow him around wearing shirts that say, "I'M WITH THE CHOSEN ONE!"

- Buy him one that says, "THEY'RE WITH THE CHOSEN ONE!" and get really offended when he doesn't wear it. Be sure to tell him you made it yourself.

- Ask if he knows whether Voldemort had any scars and if so, where are they?

- Everytime you see him, say "Do you like Luna Lovegood?" in a sing-song voice.

- Ask him if thestrals have pretty eyes.

- Re-enact his triumph over the dragon in the first task. Then ask if you can do it again on his Firebolt.

- If he asks you a question, sing the answer in at least three different styles of music and then ask if he likes to sing.

- Buy him concealer and tell him to put it over his scar so Voldemort won't recognize him.

- Tell him Moaning Myrtle has fallen in love with him and make sure he goes to ask her about it.

- Whenever it rains, use his back as a piano and start singing, "Remember When it Rained" in a loud and terrible way.

- If he does or says something unusual, say, "Don't worry. We'll call St. Mungo's and get you the help that you so desperately need."

- Ask if Muggles can see his scar.

- Run up to him giggling and say, "Romilda Vane says you have a tattoo on your chest. Can I see it?"

- Tell him that if he dies defeating the Dark Lord, you want his broomstick.