I live in Northern VA and we do a lot of sightseeing when friends and family come to visit. We decided to try the "Monuments at Night" bike tour because we thought it would be fun, we'd get some exercise, and it would be neat to see the monuments at night.]
Our tour guide was Ben, a recent local graduate. He was patient with us, he didn't ride too fast or too slow, and he was knowledgeable. We wore helmets and orange reflective vests and got going. We rode to the Jefferson Memorial, FDR, Lincoln, Korean and Vietnam War memorials, the Einstein statue, WWII memorial and the White House - we had some extra time so we rode to the Capitol as well. They give you water and snacks and time to get out and take pictures and wander around each monument.
I imagine it's difficult to take this tour during the day if the crowds are big - but it was just great at night.