What was until recently an abandoned garage is now one of the best eateries in Denver. Perched on an off-the-beaten Highlands location, Root Down is colorful inside and out, but perhaps best defined by a single hue: green. This is one of the most sustainable restaurants I've ever encountered, from the reverse-osmosis water system to the local foods, to the recycled materials throughout. Featuring a number of vegetarian selections, the fare is healthy and utterly distinctive, from sliders made of veggies and Colorado lamb to country-fried tofu to roast chicken with a green chile grit cake. There is also a new Root Down at Denver International Airport in Concourse C ([tel] 303/342-6959).