Bata Shoe Museum
One of Toronto's more unusual attractions, the Bata Shoe Museum tells the story of footwear through the ages. Much more interesting that it sounds, the building is worth a look if only to check out its unique deconstructivist architecture, meant to resemble an opening shoe box.
Royal Ontario Museum
The ROM is Canada's largest museum, displaying everything from preserved Egyptian mummies to live Madagascar cockroaches. It's must-see for anyone with an interest in cultural or natural history, and a terrific place to wander through. The first floor's East Asian Exhibit is particularly beautiful. Be aware that the museum is can easily take more than a day to fully explore. A new civilization wing is currently under construction, apparently designed to resemble the Louvre pyramid exploding.
Casa Loma
In 1911, financier Sir Henry Mill Pellatt decided to construct Canada's largest private residence. The resulting European-style castle is now a Toronto landmark and popular tourist attraction. The gardens are particularly beautiful.
The Spadina House Museum
Adjacent to Casa Loma, this museum gives a more authentic version of Canada's history. It's also a cultural centre, hosting music and art events. Hours and admission vary with the season. Check the website for what's on at the moment, or call their event hotline at 416-338-3888.