Check out Millie & Al's on the main strip in Adams Morgan. Go early (before 8pm) and get some cheap beer and some of the best pizza in town. Family owned for years and the kitchen staff has been there for years too. It turns into a crowded, loud, beer hall starting around 9pm, so go early and enjoy pizza. Other items on the menu should be avoided, the burgers are terrible and most everything else is terribly greasy. But the pizza is grand.
The guys at Capital Hill bikes are a good bunch too.
If you have access to a car, drive 66 all the way out to Front Royal and see Skyline Drive. Bring your bike, park at a trailhead and do some of the most beautiful hill climbing you'll ever do. You can see deer, bear, all sorts of things. Mountain biking isn't allowed in the park, but you'll get a killer workout on the road bike.