Hordes of like-bodied folks flock to Springfield, and are opposed only by the local Reverend, who refuses to hear the voice of reason, creating a business opportunity, taken advantage of by Homer.
One of the characters comes out of the closet, potentially gets corralled into something he/she didn't expect, but it all works out in the end. Homer gets ordained by a website-based operation that provides printable dogcollars, and gets a brainwave for a reality show which he pitches to Fox in a brilliant self-referential (same network) send-off.
If you have a idea about a show that is a ripoff of another network's reality show, press 2
The gay marriage issue, and other ideas are parodied well, if too briefly. The creators have promised to deal with these themes frankly going forward. In the next, bonus episode, Marge confronts Homer about his trove of erotic magazines, to humorous effect.