Right before I took the tour of the Wilson House the guide said do you have a cell phone. I thought he was going to ask me to turn it off. But instead he gave me this brochure. It's called Call-o-Rams: A Cell Phone Audio Tour of Embassy Row. You can see a small part of it below.
What is is as it says. A cell phone tour of Embassy Row. It starts at DuPont Circle and goes all the way to the Vice President's House. Each of the stops in numbered. It gives the name of the stop like if it's an embassy or a park. You call the phone numbered provided and then enter the number before each of the stops. You then get a description of what you are looking at. Really great idea.
In fact the Phillips Collection was doing the same things with some of its paintings. There was a phone number to call and then a number to enter to get a description of the painting.