The Refilling Dog Bowl is a pretty good sight gag, and it actually has a practical purpose. Place a 2-liter bottle of water (or your pet's favorite beverage) in the tank and it will automatically keep that mini-loo full of fresh fluids.
Just make sure your kids know it's the dog's bowl and not theirs. Made of glazed ceramic just like the real thing, the $15 bowl is just over 10 inches high, so only the tiniest wee ones will be tempted to wee here.
Product Page [Collections, Etc., via OhGizmo]