A glowing smile charms irritable librarians, stern highway-patrol officers, and reactionary judges with their big, fancy ideas about driving through the library. Rev up your smile with this Groupon. $59 for an In-Office Teeth-Whitening Treatment ($329 Value) During a single appointment, technicians coat sullied chompers in a whitening solution and flash smiles at a blue LED light in two 20-minute increments. Teeth brighten up to eight shades, and the treatment is gentle on sensitive teeth. Groupon holders receive $30 off additional services.