Critical Mass in Manhattan on August 25 kicked off much like similar rides in Paris, Japan, San Francisco or Brooklyn. About 150 cyclists gathered in Union Square to the sounds of marching band music, uniformed dancers and a speech marking the anniversary of Hurricane Katrina. About five minutes into the ride, it seemed to be more of a memorial to the First Amendment right to free assembly than a celebration. The ride was quickly halved in number as phalanxes of cops rode into the group on spanking new mini scooters, grabbed people from their bikes and . gave them traffic tickets.