I recently saw the episode of Family Guy where Brian's (their anthropomorphic pet dog) gay cousin Jasper wanted to get married to his (human) lover.
I couldn't help but notice that they ignored the most obvious joke; soon we'll be allowing people and dogs to marry. It seems to me that at some point that should have come up, like someone saying "Gay marriage? What's next? Marrying your dog?" And Jasper looking around nervously at that, or perhaps the marriage gets delayed at the end because of it.
That would not only be obvious, though, it would be funny, a lot more funny that 50% of the hit-or-miss pop culture references in the show. (They only work when the people think to actually do them in character).
That is all.