Sorry if this is old-news/repost... But just for those of you living in Southern California there's a government sponsored mower exchange currently. I just recently found out about this (1.5week prior to the registration) from a friend of mine when we're talking about mowers...

http://www.aqmd.gov/tao/lawnmower.html

I actually just turned in my roughly 10yr old gasoline mower this past weekend for an emission-free mower. Tho I haven't yet had a chance to try it after the battery finished charging. Looking forward to it tho. :-)

FYI the process itself was fairly painless. I just registered, loaded up the mower in the back, then drive up to Pasadena...