Yesterday, as many as 500 Occupy D.C. protesters assembled outside the city’s convention center to demonstrate against a conservative conference being held there, the Defending the American Dream Summit. Protesters told the Washington Post that they wanted to keep participants from leaving, many carrying signs attacking the billionaire Koch brothers, whose Americans for Prosperity group organized the summit. (Among those speaking, current GOP front-runners Mitt Romney and Herman Cain, undercover videographer James O’Keefe, as well as no-tax fanatic Grover Norquist.) The occupiers also held up a charter bus trying to leave the premises, apparently scuffled with motorists and neighborhood residents, and even blocked roadways, leading to three individuals getting knocked over by a car — they were taken to a hospital with “non-serious injuries.” Police say the driver was not cited because he had a green light, stating there were witnesses who claimed the three protesters “either ran toward or jumped in front of the moving vehicle.” A version of events in the New York Post has protesters yelling “shame” at the driver, suggesting that something more deliberate took place. Never a dull day with these Occupy folks.