Root Down is quite possibly one of the most amazing restaurants I've ever eaten at. The space itself has a cool retro feel and the food is self described as "globally influenced seasonal cuisine". They cater to various dietary restrictions such as vegetarian, vegan and gluten-free. Go with the 3-course menu for a full experience, and I highly recommend the Pepper Blossom cocktail. They also have a location at the Denver airport (I ate there a second time on my way home, it was too good to resist).