If you'd love to see one of the true gems of the DC region (and not far from the wedding reception locations)...go for a quick walk or hike to see Great Falls! It's a beautiful park (if you have a national parks pass, bring it for free entry) with majestic falls, cliffs, sights and sounds. And an easy walk on paved path if you just want to see the falls only.

First time visiting the nation's capital or just want to see your favorite bits of Americana? Here is a handy website & list of options.