Bike and Roll (Bike the Sites) gives an introduction to Washington, DC by day or night -- by bike! For kids 9 and under, ask for trailer carriers or tandems.
We booked the Monuments at Nite tour with Bike 'n Roll DC, and it was the best tour of our trip! The guide was wonderful with all the kids, and very knowledgable. We got a great overview of all the monuments, plus cruised around the whole Mall in three hours. Our feet were saved!
The tour was lots of fun, and safe for the kids. I'd recommend it for kids 6 and up, because you do have to listen to instructions and ride along sidewalks and streets. It's not strenuous.
The tours meet at the Bike 'n Roll kiosk at L'Enfant Plaza, on the far side of the Mall. We took the Metro; just walk up the stairs once you reach the street and you're there!
We actually left our kids with the family and did the evening monument tour. With our limited time it was a great introduction to DC. I did notice that they had bikes with trailers you could rent and this would have been a great option for us if we'd had more days to visit the monuments with the boys.
The staff was very friendly and knowledgeable and had all the equipment you would need!
We didnt plan on renting bikes until we walked past this place! What a great idea! We got to see alot more of the city than was planned and it was great for the kids. They offer tandom bikes for the younger ones (with DC traffic this saved my nerves). You just have to make sure you dont do it on an overly busy day. We were here for the 4th of July and biking around with small children would have never happened!