There are a few examples of public transportation in the world that double as fun things for tourists over and above their practical uses for commuters. The Chicago El's Loop section, for example, or New York's Roosevelt Island Tramway.
In San Francisco, tourists mob the cable cars, pushing regular commuters aside, and removing them from this category. Same, to some extent, with the Muni F-line streetcars. but near the convergence of the F and California St. Cable Car is the Ferry Terminal Building, which, despite its transformation in the last 20 years into an urban market, actually has ferries. I took one of them yesterday.
I had to get from the city to Sausalito. The Sausalito Ferry is, it turns out, the best way to do that. The $4.85* fare not only gets you to Sausalito, but it also gives you this view:
The whole trip is like that. In fairness to the city, it wasn't as gloomy as it appears in the photo; I just caught it at a particularly dramatic moment.
Upon disembarking in Sausalito, however, this sign greeted me:
I have no idea what that means, especially since without cholesterol, animals die. But, hey, it's California, and no one from the Sausalito Police came to steal my cholesterol.
* It's $4.85 if you have a Clipper Card. Otherwise it's $9. If you regularly travel to a particular city, I recommend getting a transit card.