Aside from the type of sushi you will find at most sushi bars, a California Roll is the notional name for what is done when a driver proceeds through a stop sign at a near-stop - that is, s/he doesn't quite come to a complete stop when proceeding through. (This is illegal, but I won't tell if you won't.)

The etymology of the name is unclear, but it seems that it has something to do with the fact that nobody in California knows how to drive.