This medieval castle is a play tent you can unfold to a six foot structure or pull it all the way out to a 24 foot diorama. It folds flat for storage. The castle has four towers. Great for creating a medieval fantasy play space in your backyard! I'd probably want to provide medieval costumes or some sort of fantasy dressup outfits for the kids to enhance their playtime.
For a more substantial (and more expensive) castle playhouse option, here's a Princess Quebec castle playhouse. Eight feet tall, it has 40 windows and looks like it would take quite a few hours to put together and install.
Your kids may or may not watch fantasy sci fi show Dr. Who, but adult geeks will get a kick out of watching them enjoy this inflatable Tardis anyway!
Young Harry Potter fans can act out scenes from their favorite book or movie in this Hogwart's play tent.