Crested Butte is having 3 weeks of free skiing this year -- Nov 25th through Dec 15th. No CO resort is ever open 100% that early, but the amount they do have open varies on the snowfall amount they get of course. On average, most resorts in CO are ~30-40% open that early in the season. By late January/early February, almost all are at 100%...unless they get an ungodly amount of snow sooner.
Keystone and Loveland are always trying to outdo each other every year on being the first to open. Both will have their guns running whenever possible, even if it's just for one or two runs. If one or the other says they are opening on such-and-such date, the other will try and match it or beat it by a day. I remember in the past when Loveland would announce their opening day, keystone would match it but would turn on their lights at 6am just to say they beat Loveland. It's all about bragging rights and being the first in the US to open for the season.