Massage professionals started using volcanic rock during their treatment sessions after messy, failed attempts to heal aches and pains with hot rock candy. Avoid sticky shoulders with today's Groupon: for $40, you get a one-hour hot-stone massage from Jodi Emdy at Salon Gianna (an $80 value).

Jodi Emdy, the licensed massage therapist at Salon Gianna, employs soothing heated basalt rocks to loosen tense muscles during a therapeutic 60-minute massage. Skilled kneading gets gently inside toasty tissue to release built-up toxins and untie complicated sailing knots in the musculoskeletal system. With the aid of her powerful pebbles, Jodi improves the circulation of blood and oxygen throughout patients' bodies and demonstrates her ace stone-skipping skills on the placid surface of Trapezius Pond.