Early humans believed that hair was actually the tentacles of an octopus living inside their skulls—an amusingly quaint notion now that modern science has proved it's technically a cuttlefish. Indulge your inner invertebrate with today's Groupon: for $132, you get a Keratin Complex hair-smoothing treatment at Salon Sollievo a $265 value). Inside the relaxed and modern mane-management facility, Melanie Van Zee, a certified Keratin Complex stylist, takes unhealed hair in hand and heals it with a keratin treatment—a chemical-free smoothing service that infuses natural keratin into cuticles, adding shine and manageability while ensuring that your morning hairbrush fight won't come to bloodshed. Any type of tangled, frizzled tresses, including bleached or colored locks, can benefit from the treatment, which lasts for a total of three to five months.