According to AFP's report on Al Gore's Live Earth held today in Washington, D.C.:
"A few hundred spectators turned out for the concert, which began at 10:30 am (1430 GMT)."
A few hundred? I guess that it isn't such a good idea to hold a concert in the summer in Washington, especially shortly after a holiday. Gore, as a former senator who has lived much of his life in and around D.C. should have known that.