Mountain Biking
With all that great terrain, you'd think the Canadian Rockies would come close to being mountain bike nirvana. As it turns out, national park restrictions tend to limit things quite a bit, but the amazing options just outside more than make up for this.
National Parks
Far and away the best of any of the National Parks is Jasper National Park which has a good network of old hiking trails available to mountain bikers. Banff National Park has less, but this has mostly been purpose-built, so overall it's almost as good.
Bike towns
It's just outside the national parks, in Kananaskis Country and around towns like Canmore, Hinton, Golden, but particularly Fernie, that the trail networks really explode.
Ski resorts