Amtrak has a good deal on its Capitol Corridor route now through April: Travel for half price on Saturdays and Sundays. The Capitol Corridor runs from San Jose to Auburn, CA, with stops including Oakland, Berkeley, Davis, and Sacramento. You can either get two-for-one tickets or 50 percent off if you're traveling solo.
You need to buy your tickets at least three days ahead, and there are a few blackout dates in late December. Learn more and book through this discount page. I'm taking advantage of this deal for a day trip to Sacramento, where many attractions are an easy walk from the Amtrak depot.
