I am only piling on here, but this has to be one of the most amazing spots in Toronto.
Take the ferry to Ward's Island for a bike ride, dinner at Rectory Cafe, or a sunny day at the beach. It is like going in ten minutes from a massive, crowded, unplanned, treeless megalopolis to a quaint seaside village. Wait, it's not like that, it is that!
The ferry to the island is 7$ for adults and less for kids. Be sure to check the schedule before you go to make sure you get back to the mainland.
This spot is ideal for relaxing, the beach, play lying frisbee golf, riding bikes, or having a picnic. I have heard others rave about the islands for a while, I am glad I experienced them first hand.