There's a great hike not far from Auburn. You pass through Cool, California (what a great name, but there's not much of a town there) and then through Georgetown.
For directions, check out the University Falls event posting for August 29th, 2010 on the Sacramento Trail Mix site.
The trail is all down hill to the falls. You follow a fire road and then head down a dusty, fairly steep trail for the last quarter mile.
There are several levels to the falls and you can hike down to the lower level for a great area to relax, have lunch or even do a bit of yoga. The area is so conducive to practicing yoga, my son spontaneously decided to practice his table pose and help a yoga-buddy into a posture.