For my sons 5th birthday we had a Scooby doo theme. We pulled out all of are halloween decaoration and made a haunted house in are basement. It was June  so we had to make some of are own decorstions. We had abot 5 or 6 large styrofome pumpkins So we stapled on the bottom of the pumpkins; sheets(for ghost) and old thrift store cloths stuffed with news paper (for zombies). Then we hung them up with fish line.  I made pom-pom spiders. Homemade do not enter signs out of construction paper, Red paint and my childs hand. We had a pair Hulk gloves that we stuck to the wall and made cage bars around it. I traced my childrens hands and made bats. We couldn't find a black light and didn't want to use a strobe light(if you use a strobe light make sure to ask parents if there child has siezures because strobe lights can trigger them) So we used christmas lights and the outside light up halloween decoration. We also had the older kids 10yrs and up dress up and run the haunted house.  So we could keep the Haunted house 5yr old scary. and the bigger kids would still have fun. At the end of the haunted house was there treat bags.    But before they could go into the haunted house they had three "clues" they had to figure out. The 1st one was "Find the all ghost then you will see, the 2nd clue to are mystery".  And I made tissue paper ghost suckers. and had a scavanger hunt. One of the clues was taped to the suckers.   The second clue said "do you want something yummy, go ask your mummy". So they had to dress each other up like mummies in toilet paper. In one of the rolls I placed the next clue.     The third clue said, "If you want the Next clue, look on the nose of scooby doo". And the played pin the nose on scooby due. I used a scooby doo punching and made noses out of black construction paper.   And then the final one said  "To finish your task, you'll have to see some scary masks.   the kids that were scared to go in did get a treat bag.  By the end of the party all the kids were running in and out there it was great! I still have kids ask if they can go in my haunted house.     Are table center piece was boiled cawliflower(brains) on top of spaghetti (intestines) garnished with peeled grapes (eyeballs) dried cranberries(blood clots) and plastic bugs. Are punch bowl was a plastic couldron. The rest of are decorations; streamers, table cloths ect.. were scooby doo.