I've been caught in the rain a few times now. It's not been so bad because it was on the way home and I can shower and dry off there. I have kind of a windbreaker shell that I wear when it gets sprinkly out, but it doesn't really stop water infiltration. It's more geared to keeping some measure of body heat in. I also usually ride in shorts rain or shine. I guess I'm kind of oblivious to the weather most days (just keep pedaling no matter what they throw at me).
However, it does make me wonder what everyone wears when they know it's going to be raining. Are rain ponchos the vogue? Helmet covers? Gloves? Or do you just pack your clothes in a watertight bag and try to find a place to hang your riding skivvies to dry at work?