In the winter, my bike gets ridden in the rain every day. I usually just put it away wet. I make sure the chain stays relatively clean and well lubed. Once a week or so, I'll put it on a mechanic's stand, pull the wheels off, and give it a good cleaning, get all the gunk out of the drive train, and relube the chain.

I keep a bucket of bike-cleaning stuff right next to the mechanics stand so this is a very simple routine, takes 15 minutes or so, tops.