I'm so excited to be planning a family trip to Canada with my kids (two girls 15 and 13) for the first time! We have decided to stay at the Sheraton on the Falls, but haven't found any deals. The hotel looks beautiful!
I would love to surprise my husdand with going to a Toronto Blue Jays game on July 2 for his birthday (still working on this). Any other suggestions from things to do in Toronto?
CN Tower is right beside the Rogers Center, so it is a good place to go before or after the game. If you book the restaurant for lunch/dinner, the ride up to the top is included, so price wise it is actually not a bad deal.
Centre Island is good for a picnic, there is also a small amusement park on the island, but your kids maybe a bit old for it. You can actually rent boats to paddle across if you're brave.
The Toronto
CityPass offers admission several attractions in the GTA area for ~60.00 a person.
The Toronto Zoo will have a set of new Pandas on display by July. Probably worth a visit if you have never seen Pandas before (July 1st being a national holiday, that weekend will probably be busy). North of Toronto is also Reptilla, a mid-sized reptile zoo. African Lion Safari, a safari style zoo, is located about 1.5 hours outside of Toronto (should be on your way from Niagara into Toronto).
High Park has an annual "Dream in High Park" festival where they put on plays in an outdoor amphitheatre during the summer. Admission is by donation, suggested is about 10.00 a person. Bring a pillow or your bum might be sore after an hour or two.
If you want something more ethnically unique, visit Pacific Mall in north Toronto - it's an Asian Mall with lots of unique shops and restaurants. Toronto for that matter has good ethnic food of all types, especially Greek, Chinese, and Japanese. Only warning is that the Chinese food in Toronto is not chicken balls and chow mein, which are available the Mandarin Buffet if you want it, but authentic Hong Kong style food (Sweet and Sour pork and Peking Duck are always safe tasty choices

). While you're up in Markham consider visiting Unionville a small turn-of-the-century town for food or perhaps go for dim sum at one of the many Chinese restaurants up there (i.e. Dragon Boat Fusion Cuisine or Spring Villa Chinese Cuisine ... expect a line up on weekends). Black Creek Pioneer Village is also in the "area" about 20 - 25 minutes away.
Outside of the city, you can visit Stratford, ON (2 hours west) which holds a fantastic Shakespeare festival each year (along with popular musicals too). St. Jacobs Market is also near Stratford.
Toronto also has a couple great musicals which you may want to see before leaving; you can order tickets from mirvish.com.
Here is a good list of major attractions:
http://www.toronto.com/guides/major-attractions/