Get off BART at the Embarcadero Station. You should be near the end of the Cable Car line that runs along California Street...

If you've picked up a "passport" you can ride for free (see the Public Transit section above). If the ticket machines are broken (suprise) you can hop on the first cable car, and give $5 to the conductor... note that if you're planning on riding back on the cable car, that will be another $5, and cable car day passes are only a little more than twice the ticket price, so maybe you should just buy a day pass. You could probably even sell this pass to someone else to your mutual profit. But that would be wrong.

When you get on a cable car, you really want to sit on the outside benches, or even better, stand up and hang off the outside of it (the corners are the best). One of the reasons you want to ride this cable car line, and not the Powell street one, is that you're more likely to be able to get whatever spot you want.

You can get off at Powell and transfer to the other line (note: not a free transfer, unless you've got a day pass): at least the wait will be shorter than it is at that zoo down at Powell and Market. Though personally I just recommend staying on the California Street line, and riding up Nob Hill.

The trouble with the California Street cable car is that once you get off at the end of the line, there isn't all that much there. But you can backtrack one block, and poke around on Polk street... there are a some cafes and bookstores in the neighborhood and just north of California you will also find one of the highly recommended "See's Candies".

You might want to ride the next cable car back, possibly to the corner of Kearney and California, where you can pick up the "walking tour" version of Northern Expedition #2, described below.

Or you could ride down Van Ness on the 49 bus, and start looking around in the Mission, or you might even consider diving down into the "Tenderloin" (see below).