In Toronto, we went to a number of fun places with the kids.
One thing we can recommend is the Kidstown Public Wading Pool in L'Amoreaux Park, Scarborough. I'm not sure if it's worth an hour's drive, but it was definitely worth the ten minute drive from my parents' house. But to call it a Wading Pool is like calling the Hindenburg a balloon. There are all sort of mechanical devices filling with water and tipping over to splash kids, slides and sprayers to run through, and (Austin's favorite) whales to sit on and pump back and forth that will shoot water out their spouts at other people. Lots of lifeguards on duty, a hotdog stand just outside the gate and it costs $1 per child to get in (no charge for adults). Amazing.
Turns out there's also a nice water park in the Toronto Zoo now. This one has environmental themes as you see how water comes from rain, feeds wetlands, goes down rivers and into the oceans and the polar caps.
The Toronto Zoo is a great zoo and we saw lots of great animals, like rhinos, elephants, red warthogs, polar bears, and most amazingly, baby Sumatran tigers! Here's the zoo's tigercam!
We also visited the Chinese Lantern Festival at Ontario Place. This was pretty special: artists were brought to create light sculptures that illustrated either Chinese history and culture, or more modern designs, like Toronto's CN Tower, or dinosaurs. This is going on for a few more months; if you want a coupon, go to this site. More pictures on Flickr here.
Toronto in the summer is great for kid visitors and their parents.