Was inspired for this by the discussion about making a giant hamster ball. The idea here is a little different: set up something akin to the oversized maps like Bedroom, but do it as a pet store. Use hamster tubes, aquariums (some of which could be deadly, and marked as such with all save a few spots covered with wire mesh), use various pet toys as walls and barriers, have, say, a spawn room as a turned-over box of dog treats, and so on. You could even have a hamster ball, after a fashion: have a large, open area that has some good reason to cross it, with boundaries on all sides. Now put a giant hamster ball in it, and set it up so it's a physics object that does damage. Entrances are safe, and maybe a few other small spots, but otherwise you've got this giant, potentially dangerous (or even lethal with a couple hits) ball that can be moved around the area. Could work as a payload, CP, or even CTF map. Or combination/variation thereof.