Just thought I'd mention two sort of wedding related facepalms I ran into lately.
First, I receive a wedding invitation from a family member. Really nice invitations, but marriage is mispelled. Poor thing. I'm not making fun at all because that's totally something that would happen to me. Sucks, but what are you gonna do?
Second, and more head-desk worthy is a girl I sort of know who just moved into a new apartment with a roommate. They registered for house-warming gifts. And they're not having a house-warming party. And since there is no house-warming registry, they registered for a wedding registry.

Anyone got any good ones to add?