First, you find some average/homely chicks in your office and become mildly acquainted with them (first name basis will do). Then, next time your wife comes to the office (party, event, or just have her bring you lunch or something), you introduce them to her. Afterwards, you tell her that those were the "hottest chicks you've ever seen."

This is a gambit though, because if you pass the whole thing off as a joke, your wife might think you are hiding something. If she believes you, then she might become very self-conscious about her looks. You have to be VERY careful about which girls you pick. If your wife is an 8, you need to pick a girl who is in the 6-7 range. If she is a 10, good luck!

The chances of making things worse is greater than making them better. Just like Vegas, the house wins.