Amazing scenery, an relatively easy trail and a teahouse make this a very popular trail in Banff National Park. If you're willing to forego the teahouse, it's also a great shoulder season hike, at least before any significant snowfall creates avalanche risk along the route.
This one is a long day, especially if you spend any time exploring the geology of The Onion or searching for "ice caves" along the edge of the Wapta icefield. It fits the definition of a Class 1 scramble. The toughest bits are getting up and over the chokestone and then going up the rock ledges above Bow Hut, to The Onion. The views from the summit are well worth the effort.
An easy, half-day winter hike/snowshoe to a narrow mountain lake. Expect to share the trail with skiers, snowshoe hares and spruce grouse.
Fall is a great time to undertake the long hike to Aylmer Pass in Banff National Park. Next time we'll do the Lake Minnewanka Trail portion on mountain bikes so that we have the time/energy to make the side trip to Aylmer Lookout.
Most of the hiking guidebooks we own strongly recommend the trail to Sunset Pass. But the trailhead is a two hour drive from Canmore (three hours from Calgary). That's a pretty big investment of time and gas money. So this one stayed on the "someday" list for years before we finally got around to it in mid-September. Too bad we put it off for so long!