Around the great lakes areas there are several National Parks that offer excellent hiking and mountain biking through mountains and forests: the most accessible of these are Killarney Park in Ontario, and Mont Tremblant Park in Quebec. Should you fancy a bit of white water rafting, then you should head to Nova Scotia's Kejiumkujik National Park.
There is excellent alpine skiing in the Rocky Mountains in the west of Canada, particularly around the resort town of Whistler, although there are many other smaller resorts throughout the country.
There are many cruise routes up the coast of Canada, and some of these go as far north as the arctic circle, and give you the chance to get close (but not too close) to bears and seals.