Double Decker Muni Bus!
Details of the routes served, etc. are avaiable at the MUNI/MTA website, if you're curious. I took a quick tour of the bus and it's very Las Vegas-y (the bus will be on loan to MUNI, then be delivered to Vegas). Personally I think they should run this on one of the steep lines, like the 1 California, and charge extra for the front row seats up top.
If and when I get a chance to actually ride it with real passengers, I'll post more fun photos!