Idea: Commuting Buddies
If you're a comfortable bike commuter, and there are people at your work/uni/school who aren't sure how to get into commuting by bike offer to help them. Post about it on your Intranet. Put a sign on the pinboard. Mention it around the water-cooler.
Offer to help them find a suitable route to work. Offer to come by their house in the morning to ride with them the first few times. Show them the existing facilities at work. Remind them that they have to do less cardio at the gym if they get incidental cardio in during the week.
As we're coming in to more predictable and gorgeous weather, now's the time to get them hooked.
One more cyclist is one less car on the road. Absolutely worth some effort.