Everything. We're not kidding. There's an ancient saying, "If you don't like the weather in Colorado, wait 15 minutes," which is all too apt for this region. It may be 40 degrees (Fahrenheit) and windy during the day, it may be 65 degrees and sunny. It may be 40 degrees at 1 pm, but 65 degrees at 1:30pm, and it may snow at 3pm. It will most definitely be between 0 degrees and 40 degrees at night. It will most likely not rain, but there's a good chance of snow. The south-side streets and sidewalks will be horrendously icy and slick, those on the north side will be refreshingly dry. At some point you'll have to cross the street.

And, of course, the dances will be hot. And if you plan on skiing, the most elevated run tops out at 12,500 feet above sea level, which tends to be cold.

Water, chapstick, and sunscreen are a MUST.

Pack everything.