Up in Mammoth Lakes CA, mountain biking. The trails up at the top of the mountain (11,000+') still have a lot of snow on them, but the lower levels are wide open and a lot of fun. I probably ended up with about 20-25 miles of singletrack trail riding, and not much in the way climbing. The way it works is you buy a trail pass for the day, and the fee includes a shuttle bus service to the main lodge and gondola service to the top. So, you shuttle up, bomb down, and repeat until you've had enough. Even though it is mostly downhill, it is a surprisingly fatiguing endeavor for me as I am mainly of a road bike rider. Roots, rocks, drops, trees, and other associated obstacles really kept me working to stay upright, but then again I'm not too good at this sort of thing. A ton of fun, though, and the views were pretty nice.
A few pics:
At the base, close to where we're staying:
Tram service to the main lodge, with Mammoth Mtn in the background:
Miscellaneous views from the trails:
My sled (pic taken in the hills local to my home) a 2009 Marin Mt. Vision that I bought at an end-of-year rental bike blowout: