Geologic activity both creates settings for yodeling competitions and gives grade-schoolers an academic excuse to mix soda and vinegar. Appreciate the pampering properties of Earth's activity with today's Groupon: for $75, you get mineral and/or mud baths for two at the Baths at Roman Spa in Calistoga (up to a $150 value).

The relaxation mavens at the Baths at Roman Spa mix their signature mineral-rich mud from peat moss, local volcanic ash, and Calistoga’s world-renowned geothermal water, which bubbles up from the spa’s underground hot springs. Slip into a tub of the earthy mixture for a one-hour soak that can help increase circulation, melt tension, and exfoliate skin. Inflatable pillows cushion soakers’ necks as amiable attendants help them sip water or play kazoo solos hands-free. Alternately, a one-hour mineral bath in geothermal water culled from Calistoga hot springs can cleanse skin and encourage relaxation. Couples, friends, and vaudevillian comedy duos can receive the same treatment and enjoy the side-by-side privacy of their own room.

After either treatment, pruney pamperees cool down in the spa's relaxation room before emerging to frolic through fountains, gardens, and private patios on its verdant grounds. Visitors can spend the rest of the day paddling in an outdoor geothermal swimming pool, swirling in a whirlpool, or looking at golems with a newfound sense of respect.