From the Metropolitan Police Department
: "This is to advise the public that the National Marathon will be held on Saturday, March 24, 2007. To facilitate this event, parking and vehicular traffic restrictions will be in effect on certain roadways. The race is scheduled to begin at approximately 7 am. All streets affected by the National Marathon are expected to be reopened at approximately 2 pm, depending on prevailing conditions." A peek at the Course Map
(PDF) shows that M Street SE, 8th Street SE, and South Capitol Street are on the course, so be prepared for road closures and other difficulties if you're coming into Near Southeast or anywhere within the course route.