(updated in response to a request for pictures)
Some English conversation schools for kids have full-on Halloween parties, large affairs with the participants in elaborate costumes. Me, I run a fake English school in which half the student population of two shares a good deal of DNA sequence with me. So it seemed fitting to have a half-assed Halloween party (but not until we went through the 18 alphabet flashcards and 30 vocabulary flashcards first). I bought some individually wrapped candy and cookies at the local supermarket, and witches' hats and Halloween decorations at the 100 yen store.
Then the Pumpkin Mommy, Daddy, Princess, Prince, and the neighbor girl took turns being the trick-or-treaters and the neighbor. The Pumpkin Daddy was assigned the role of the neighbor who didn't celebrate Halloween, and got TP'd. When planning this "party," I'd considered having them TP the house for about 0.02 seconds before deciding against it. I mean, how are you supposed to explain the concept of TPing to a neighborhood of Japanese folks in their 60's and 70's? When the Pumpkin Princess and the neighbor girl started turning Daddy into a Mummy, the Pumpkin Prince started crying "don't hurt Daddy!" so we had to stop.