Just a couple hours out of town is a series of cave systems in Calaveras County, aka Gold Country. There may be upwards of 300 separate caves in this area, with at least five of them built around giving guided tours. Most offer short simple walking tours for a casual look, but a few also have an "adventure" tour that involves crawling around in some pretty tight corridors. Caves temperatures stay pretty constant, equal to the average surface temp, so this is a good winter activity.

Required people: 1+, but a large group 4-10 is a better bet as you'll be traveling in a group. Our group of 9 was getting a bit to the unwieldy size but you'll enjoy yourself more with friends.

Required gear: hightop shoes and clothes you don't mind seeing get extremely dirty, perhaps beyond salvation. The outfitter will provide coveralls and a helmet/headlamp. One provided kneepads, otherwise you would do well with your own *soft* pad type. The coveralls may be a bit grimy, and defintely prone to tears, so you might do well with a thin long sleeve shirt, and shorts with a bit of padding. Wear too much though and you may overheat, increasing your discomfort in the constricted areas.

Required time commitment - full day round trip, or a weekend.

Costs - the adventure tours run in the ballpark of $99-130 for a multihour excursion.

My Caving Trip - In 2003 we went to Moaning and California Caverns.
Tunichil - my caving experience in Belize.
Moaning Cavern
California Cavern