I thought I was familiar with most places in the GTA but I hadn't even heard of this place before! It's tucked in Centennial Park and surrounded by activities that are well known like the batting cages, go-karting, and slopes. If you want a breather from those things, you should definitely check out the Conservatory. Bonus points for Free Admission, although you can leave a donation.
The place is well maintained and pleasing to the eye. Their permanent collections boast plants and flowers from different climates in the separate wings. They even have living creatures: turtles and fish in ponds, birds in cages, and I even spotted a squirrel running rampant in a bush. They also have special events running at different times throughout the year, so they seem active even though it's not busy at all. In fact, there were only 2 other people wandering around when we were there. Venture a peek outside by the bridge and pond with the Red Japanese Maple tree because it's a beautiful place to take pictures.