I know, hard to see, but he's the squat little character in white on the left. He sometimes pauses his amplified rants to chat with passerby.
I've never been able to figure out what triggers a CCHBG appearance, but, like Frank Chu, he is often attracted by gatherings in front of City Hall, of which there are many. Unlike the Chu, he comes even where there aren't television cameras present. Today there was a whole Bike-to-Work Day thing set up in front of City Hall, and I guess it was like a salt lick to a deer for CCHBG. As I write this, right this instant, the Bike-to-Work thing is gone, but CCHBG is still out there ranting. When I walked by he was screaming something about "ideology" and "San Francisco" but, much as that could be direct from Bill O'Reilly, it was hampered by the absence of complete sentences, which O'Reilly manages to accomplish occasionally, although he and CCHBG work at about the same level.
Sometimes he shows up when City Officials are having some kind of Official To-Do on the steps with a podium and mikes and TV cameras and it's fun to watch the deputies who do security for those things surround him like a Flying Wedge and inch him away from the steps so he doesn't get in the shot. They also seem to be good at talking to him and distracting him from using the bullhorn long enough for some supervisor or another to get through their announcement about Take Your Marmot to Work Day or the Green Blender Initiative or whatever silliness they're wasting our money on today.
So carry on, CCHBG. You're not appreciably nuttier than lots of your fellow citizens; you've just got the bullhorn to loudly advertise it.
UPDATE!!!!! Helpful reader Lindsey sends along this much better pic of CCHBG. Thanks, Lindsey!