Have you biked yet this month? Have you commuted to work, ridden to school, taken a spin in the park, picked up some groceries or biked to the ferry? If you have, you're eligible to enter the Bike to Work Day Raffle organized by 511.org, going on through May 31.

Four new bicycles and a commuter kit from REI make up the top prizes, including a Grand Prize Larkspur bicycle from Marin Bikes.

Anyone taking their bike for at least one trip during May can enter! If you haven't had a chance to ride yet this month, see WalkBikeMarin's "I Want to Walk and Bike " page for resources on how to get started.

Sign up for the raffle here.