I stopped by Michael's the other day and saw these sitting on a shelf. They might make great terrain for D&D, miniatures war gaming (the palace in particular looks great for Ambush Alley), and so on. They were about $7 to $9 a piece.
UPDATE: These things are actually birdhouses. You can also find them on eBay if you search for "unpainted wooden castle." I can't find them on the Michael's web site.