From the Living Social offer
The easiest way to get around town isn't by hopping in your car or hailing a cab. Fill your lungs with fresh air and take a ride with today's two-wheeled deal: Pay $12 and get a month-long membership (regularly $25) or pay $37 and get an annual membership (regularly $75) to Capital Bikeshare. Any local knows the best way to zip from the West Wing to Watergate or from Crystal City to Capitol Hill is on your bicycle. But finding the right place to tie up your steed can be a pain. Capital Bikeshare lets you take a pristine and shiny red bike for no charge for up to half an hour, allowing you to get back and forth between dozens of conveniently located bike stations in the District and Arlington. Those perfectly toned new legs? Just a pleasant side effect.
Sign up here. Sign up here, and I'll get a free membership. Sign up here and GGW will donate the credits to WABA to use as part of their East of the River initiative (which is what I'll do too, after I give one to my brother-in-law, who thinks he needs to buy a scooter to get to work).
And it does work if you're extending a membership, which is what I did.