Trinity Bellwoods Park
Home to the largest white squirrel population in the world is our beloved park, Trinity Bellwoods. It was formerly the site of the college, now situated at the University of Toronto (and my alma matter!).
Year round, this is a fantastic place to visit. Whether you want to run, play tennis, some croquet (and you can get the equipment at the local Trinity Tuck Shop open seasonally -- http://trinitytuckshop.tumblr.com/) or picnic, you can do it here.
Tons of events are held here too including Nuit Blanche and the Art Crawl in September.
PS There's a coffee shop called White Squirrel across the street. There's also a fish and chip shop called Chippy's and Nadege, a french pastry shop that also sells sandwiches and has a sweet patio view of the park.