Ask HN: Rent a car for pycon?

I am attending pycon for the first time next week, and visiting the valley for the first time. I was going to rent a car, but thought I'd ask first. I've rented cars at some conferences and driven every day, and sometimes it sits parked at the hotel the whole time. Any thoughts on whether having a car at pycon is worthwhile, or is there plenty of public transportation and ride-sharing available to see a few parts of the valley?