Thanks for all your suggestions yesterday! I ended up picking a totally Elaine outfit (that I'm going to wear tomorrow instead). Then I woke up this morning and saw all your comments about sequins and black and changed my mind last minute. Can't you tell from the mess? (Actually, our place always looks like this...)
I wore my sequin blazer!!! Seriously, nothing else in my closet says "I'm goin' clubbin'" like this sequin blazer. Truly. I have no clubbing clothes. Why would I? I'm married. I'm a Mormon. I don't drink alcohol. I don't dance (only in front of my mirror). ...and I'm not a skank.
Because of my lack of clubbing clothes besides the blazer, I went for the classic route. I like it. It says "I'm going to party" while still being me (and clothed).