A bicyclist who apparently was angry at being cut off in traffic fought with and stabbed the motorist he believed to be responsible. D.C. police officers were called to the 1600 block of Massachusetts Avenue NW about 10:20 p.m. Wednesday for a report of a stabbing. Witnesses told investigators that a bicyclist struck the driver's side mirror of a Smart car with a heavy bike lock. According to the police report, the driver then got out of the car and asked, "Why did you do that?" That's when it escalated into a fight, which ended, according to witnesses, when the...