I wanted to give you all a heads up about a bicycle co-op here in DC called The Bike House.They run free (donations encouraged!) weekend clinics where they invite visitors to come fix their own bikes, ask for advice and get help from the volunteer mechanics, and meet other bikers in the DC area. Most necessary tools are available at their clinics, and they encourage visitors to show up with any necessary replacement parts since they don't have parts for sale.
The main clinic is run by volunteers every Saturday from 12-3pm, and will be opening on March 10 for the season at their new location: Annie's Ace Hardware, 1240 Upshur St. NW in Petworth. When the Bloomingdale Farmers' Market opens up for the season (May-Nov) they'll have a smaller clinic there as well, Sundays 11-1pm at 1st & R St NW (right by Big Bear Cafe).
The Bike House also offers beginner mechanics classes that they encourage visitors and potential volunteer mechanics to sign up for. The class is a 4-week month long series meeting Saturday mornings at Annie's Hardware, right before clinic starts up at noon.
Visit the website for more info!