Couples' costumes can be quite a challenge.

My wife and I went as Bluto and Olive Oyl (we hardly had to use costumes!)

The most gruesome "couple's" costume I ever saw was JFK and Jackie - him with a bullet hole in his head and her with blood all over her. I wasn't amused at all, but they were a big hit. Hey, we're becoming a desensitized society; last year I saw a kid go as the chalk outline! (a very urban theme)

I saw one couple go as the ultimate interfaith marriage: he was an old Hasidic Jew with a long beard; she was a nun (that wasn't you, was it, annap?) It was all the more enjoyable because he was very thin and she was, well, ample in her proportions. I also saw a hubby and wife who went as a pair of breasts.

Hope this helps.