Obviously Vietnam takes the cake (and, from what I´ve heard, the situation in other SE Asian countries is similar). This video was taken from the 9th floor of the Sofitel Hanoi with our little point-and-shoot camera. Notice the constant honking, the absolutely random way the traffic flows around the circle, and - my personal favorite - the bicycles that slowly make their way through the motorbikes and cars, many times going the wrong way!
Crossing the street as a pedestrian, as you might imagine, was one of the most insane experiences of my life. You basically step out into heavy traffic, slowly follow a straight line, and watch in amazement as everyone swerves around you like the Red Sea of motor vehicles parting. In several of our hotels, they gave little information cards to tourists that included the cardinal rule for crossing the street in Vietnam: DON´T RUN!