Two corrections are in order:

(1) The prohibition against riding on the sidewalk is not statewide; it varies by jurisdiction. It is not legal for adult cyclists to ride on sidewalks in San Francisco. There are some multi-use paths that the blithering idiotfest on SFGate keeps referring to as sidewalks, too.

(2) Single file is not required by law. Bicyclists may pass each other, of course. The notion that this applies to “narrow streets” makes no sense because, as I wrote above, those are the very streets where bicyclists may use the entire lane. (Note how @generic immediately misapplied that claim to brush away our right to use the entire lane!)

Important missed item, though: Do these rules apply to me drunkenly riding a shopping cart down a steep hill? I would not be wearing a helmet.

Also:

“Generally, cyclists are allowed full use of lanes even if a bike lane is present, however on busy or narrow streets they must ride in single file.”
So what’s busy or narrow?

It’s absolutely maddening when they take up entire lanes, double-file. I didn’t know it was illegal.

This depends on whose safety you are talking about. You are probably safer driving drunk than cycling drunk, but everyone else is probably safer if you are cycling drunk than driving drunk. Super-Freakonomics cites stats to indicate that walking home drunk is less safe per mile than driving home drunk, but this stat only includes one’s own injuries, not the injuries inflicted on others.

Annoyingly, the hatred of many cabbies hold towards cyclists often expands to a refusal to put your bike in their trunk. I let them know why their tip was so small when I don’t have my bike…