2 Couples Group Costume Ideas

Anyone have any 4 person group costume ideas? My husband and I want to do a group costume with my friend and her boyfriend, but kinda at a loss for cool ideas. We had originally wanted to do the Village People, but can't find two others to commit to the 6 people that we need. So, now we're back to thinking of a 4 person group.

Any thoughts on this one?

We want to do a specific group, not just four similar characters, like a group of zombies or something.... But doesn't have to necessarily be a group of 2 guys and 2 gals.