I once said, I'd love to see Dean and Sam to appear on The Simpsons or South Park, but I'll take this one! Supernatural appeared on Cartoon Network's MAD yesterday. Details here. I imagine you should be able to watch the entire parody on YouTube very soon. For now, here is the preview:
LOL.. I love the details they have on Dean.. Woot Woot! Show us his muscles!! As for Sam, nice work on his sides and the puppy-eyes!
And in case you missed the Smallville parody, here it is again.. Lois and Chloe look so much like Erica and Alison!