As the debate over Critical Mass and the clash between bicyclists and a minivan driver rages, two widely varying eyewitness versions of what happened Friday night in Japantown have emerged. It could be a case of a terrified family whose minivan was surrounded by angry bicyclists who rode their bikes in circles around the vehicle, harassed the driver and then pummeled the van, smashing a rear window and inflicting $5,300 in damage. Or it's a situation that spun out of control when a frustrated driver accelerated recklessly through a crowd of Critical Mass cyclists, struck one and continued driving until...