Trains and slides.
If we have enough energy, may drop by the Aquarium too.
Here's intro from City of Toronto website:
Roundhouse Park was created in 1997 on top of the southern expansion of the Metro Toronto Convention Centre. The park features the original, fully restored and operational 120-foot long locomotive turntable and a carefully chosen collection of full-sized railway equipment. It is home to the Toronto Railway Historical Association live steam miniature railway and other outdoor exhibits illustrating Toronto's railway heritage. Exhibits include the original 60,000-gallon water tower, the 650-ton concrete locomotive coaling tower and a collection of historic buildings, including the Don Station and Cabin D.