On Saturdays, I play ultimate frisbee at the National Mall. The field is sandwiched by Smithsonians and nestled in between the Capitol and the Washington Monument. The view is awesome, beautiful like the ocean panorama at my Santa Cruz field, but in a completely different way.
There's about 15-30 people who usually show up. Many are bikers, most are under 30, and they tend to know about cool places to go in the city!
Something cool just happened on the field so I stopped to watch.