OK, I've read this thread with a good deal of interest and now I'm going to chime in with my two cents.
Just go. That's all there is to it. You do not commit yourself to anything by going, you don't have to play, you don't have to participate. This nibbling around the edges just isn't healthy IMO, giving up, changing your mind, backing out etc becomes a habit...even when you know better you'll still rationalize all kinds of stuff to explain why you didn't just do it...like having to explain to someone why you need them to let your dog out. The explanation isn't difficult, we went to a party, we went to an event, we went to a show...we want a night away....
You either need to step off the edge and into the pool or just walk away and stop worrying about drowning. Just fucking go to a club or a party or meet someone off of the internet, the worst that can happen is you don't like it, BFD I bet you do things every single day that you don't like and yet you still survive the experience.