You go to any Party City or Discount Celebration Town, USA (I assume that’s a real store) in America, and you’re likely to find an entire section dedicated to Harry Potter. Poorly and cheaply made hats, plates, napkins, and balloons, all with Daniel Radcliffe’s shamefully masturbating face on them.
You can do better than that for the special Potter fan in your life.
Take the husband of Imgur user “earlgee,” for instance. His wife turned 26 years old this year, and to celebrate, he went all out. There were Hedwig balloons with letters containing Harry Potter pick-up lines (“Girl, I wanna grab your Golden Snitch tonight”), a Hagrid-inspired cake, and a Mandrake made of chocolate pudding and cookie crumbs. “Earlgee” also wrote, “He made wands for all my [party] guests out of doll rods and hot glue. He made me the elder wand as my birthday gift! (Along with a complete [Blu-ray] set of all the HP movies).”
That puts your “here’s a poorly Photoshopped photo I found of Emma Watson online that I printed and taped to the mailbox” concept to shame. Try again next year, when you throw a Minions-themed party because they’re on-sale at Target.