I spent a day on Mt. Tam climbing up the mountain in creek beds and "running" down it on abandoned firebreaks and overgrown trails. It's not a race so much as friends organizing a group run. I didn't do as well as I'd hoped, missing the very first checkpoint and having to backtrack. It was a hard but fun day.
Here's the route. Look at the vert.
Here's a photo sphere of the view of the North Bay from near the West Peak summit.