In light of several recent spats of violence and stupidity against bikers, I have begun researching some effective self defense measures that an urban cyclist can take. The following article leaves little doubt that mounting a pitchfork to the headset is probably not a good idea.
http://query.nytimes.com/mem/archive-free/pdf?_r=1&res=9E0CE6D81F39E433A25751C2A96F9C94669ED7CF&oref=slogin