The Alpine Slide at the ski area is fun for the kids. I think mountain biking is also available.
Fly fishing the San Juan just below Navajo Dam is also a good experience - invest in a guided float trip. Mesa Verde, Arches NP, Canyonlands, etc are all worth seeing. Hot Springs in Ouray or Pagosa Springs are also fun(icky to me though). There's some waterfalls just outside Ouray(I think it's called horseshoe falls or something like that).
