I don't think it's been mentioned here, but it has been in other places. The guy who brought the kids to Imaginationland appears to be based on Dreamfinder, the character who used to headline the Journey into Imagination ride at EPCOT. Dreamfinder wore a similar outfit and drove a similar airship. At first, though, I didn't think he was Dreamfinder, because Dreamfinder seemed like so obscure a reference ( Really, who remembers Dreamfinder? ) that I didn't think Matt and Trey would feature him so prominently. But I guess I was wrong. The kids ARE rescued by the dragon from "Dragonheart". Talk about obscure.
EDIT: Oops, sorry I didn't see your post before, Hordesman.
BTW: We did see Astro Boy, the Flash, and Mighty Mouse in the ep. It stands to reason that all the great superheroes are there as well. So why didn't they fight back? How could a pathetic bunch of terrorists beat all these superheroes?