Or get a rental car and drive SW - Niagara Falls, while kitchy, is still pretty cool to see, plenty of wineries out that way to indulge in, some very nice countryside to drive around if so inclined.

The small neighbourhoods in Toronto are a treat to walk around in, browse the stores, sample the food, talk to the people. That was one of the biggest advantages I saw about Toronto when I lived there a while back.

Toronto also has a pretty good zoo (go early) if you like that sort of thing.

The Harbourfront is usually pretty interesting for people watching, eating and drinking at the various vendors, or catch the ferry over to the Island and rent a bike and tour around it for the day.