8. Guyot Designs' Firefly $20
Industrial designer Joshua Guyot, 31, created the Splashguard, a silicone disc that fits over the opening of a water bottle, after getting tired of being splashed each time his wife accelerated on a twisting mountain road. The spill-proof top became Guyot Designs' first product in 2002. Today, the Deer Isle, Maine, company makes seven lines of outdoor items. Its latest, the Firefly (pictured here), is an LED light that transforms any water bottle into a lantern. www.guyotdesigns.com