Centreville Amusement Park located on the Toronto Islands is open this weekend, you can catch the ferry at Harbourfront. http://www.centreisland.ca/about.html
The Old Spaghetti Factory is family oriented and kids usually love it.
http://www.oldspaghettifactory.net/home.html

Centreville is a great place for a six year old, and beats Ontario Place.

And the subway is fun for little boys. But you need to be in the front car, so he can look out thewindow, or in the last car.

For the most fun meal, go to the Rainforest Cafe, in the Yorkdale Shopping Centre. This looks to be a long way away, but the syubway goes directly into the shopping centre, and then it's just a shoort walk. Get on the subway at Dundas and Yonge (just south of the hotel) and go SOUTH to Union station and then the train changes direction and heads north again, to the Yorkdale Station.

Lots of fish tanks, roaring elephants, servers who like kids, and lots of food kids like, plus decent foood for adults.

Closest kid-friendly restaurant to the Chelsea is a Swiss Chalet on Yonge Street. Go out the side door of thehotel (alongside the cafeteria) walk a short, short way to Yonge, turn right/south, and you are almost there.

Fun food --hot dogs and French Fries from a truck in front of either Toronto City Hall or the convention centre.

My friend Max turned six today, and he had dinner at Club Lucky / Kit Kat Too, in the entertainment district, on John Street, just north of Adelaisde, across the street from Chapters giant book store. Max knows his way around Club Lucky; his dad owns the place. It's a medium fancy restaurant, but the sstaff are used to having a little boy around the place, and know how to make kid-friendly pasta or would make him a sandwich, while grownups enjoyed a good dinner.

Open Friday and Saturday; closed Sunday.

You might try Sunday brunch at the Bright Pearl in Chinatown, on Spadina a couple of blocks north of Dundas. Since you get to see what the Dim Sum is before you order it, junior will have an idea of what he's getting.

And then there's Mr. Greenjeans, in the EAton Centre, just south fo the Sears store. A couple of blocks from the hotel; excellent kids menu, and the food for grownups is pretty good too. I eat there volunrtarily even without a kid in tow, especially when I'm looking for a hamburger.

Back to street food. Some kids enjoy visiting the St. lawrence market, especially when they can see pigs heads and other gross things. Down there, back bacon on a kaiser roll is a kids favorite,a dn they can eat it outside on the balcony that surrounds the building.

And the cafeteria inside the Chelsea has lots of things kids like -- pizza, sandwiches, various drinks -- and the prices are reasonable and the quality is good, and the location can't be beat.

Don;t forget to bring bathing suits -- the Chelsea has a water slide.

BAK

Some 30 years ago my kids enjoyed Toronto Island and the Science museum and I am sure they are both better.
About the subway--in a flash my son went up a different exit and went "missing". I was frantic! The police listened but were emphatic that he would work his way to the top and present himself where we all stood.
And he did--it apparently was a common occurrence!!!
Don't you just love Toronto!!!

Don't forget Casa Loma, with its towers and secret passageways.