On Bike to Work day (or all week!), set up commuter rest stops around the community on frequented bicycle routes. Rest stops can have coffee, juice. food, bike lights, reflective leg bands, bike maps, stickers and other items from the local and statewide bicycle advocacy organizations.
Organize students to ride their bikes to school together. Bike with the kids to school or organize a bike-pool with other parents to leave the car at home. Help choose appropriate routes and take this opportunity to reinforce safe cycling practices.
Car vs. Bus vs. Bike Commuter Races! Motorists, bus passengers and cyclists all start and end the morning rush hour at the same spots, but they may take distinctly different routes (Spoiler: The bicyclist almost always wins!). This is a sure-fire media event to run on Bike to Work Day to encourage folks to give bicycle commuting a try.
Many cities host commuter challenges where businesses compete to have the highest percentage of employees who pledge to Bike to Work every day of bike week. Bonus points are given to companies with bicycle parking, safety materials, and showers and changing facilities.
Work with local businesses to provide prizes for Bike to Work Day participants. Possible prizes include: bikes, accessories, lights, racks, bags, airline tickets, and gift certificates to various local businesses. If sponsorship permits, have T-shirts or reflective commuter vests produced promoting the sponsors.
Now in its third year, the National Bike Challenge is a free ride-tracking program to encourage bicycling for transportation, fun and fitness. Participants log their miles to compete as individuals, teams, cities, and states. Regular prize drawings recognize participants who ride often or rack up mileage. The Challenge starts May 1st - promote it locally and post regular updates on your community's progress!
Ask your Mayor, City Council or Governor to officially proclaim May as National Bike Month. Sample proclamation here.
For more great ideas, check out the League of American Bicyclists' National Bike Month Guide.