I've recently got the biking bug. Been trying to clean up my Trek 4900 a little bit and taking it around the area in the company of a few friends. I'm interested in learning how to take better care of my bike and recommendations about trails and accessories.
You've come to the right place for biking.
If you do clubs or racing squads, there are several around DC.
Lots of trails, both MUP's and dirt, but some are pretty busy.
There is a good off-road site close-in in Virginia at Wakefield Park. On the beltway at Braddock Road.
If you have any questions, just post em. One of the forum members aournd here will answer.