For Toronto, if it’s your first visit, you have to go up the CN tower.Because, when you go home, people are going to ask you about it.Ripley’s aquarium, if you haven’t been to a big aquarium somewhere else already (e.g.
Monterey Bay, Sydney, any of the SeaLifes, Turquazoo, etc).Fort York, for local military history.Black Creek Pioneer village, for local civilian history.
Hockey Hall of Fame.Canada’s Wonderland, in the summer, if you like roller coasters.Go for a cruise on a party boat or tall ship in the harbour, see the skyline from the water.
Other than that, grab a copy of the ‘Now’ free paper, and look for events going on that are of interest to you, depending on your tastes.
Visit Dundas Square in Toronto.If you can, hit Niagara and go to Fort Niagara.
In Montréal you have to walk the 7 km of the underground city.
Just keep it for a rainy day.