Harbourfront centre is one of the best locations to view the beauty of Lake Ontario in Toronto. They have a wooden walkway where you can walk by the shore beside the centre. During winter, you can skate for free (if you bring your own skates) and it is the largest outdoor skating rink in Toronto. In the summer, they organize cultural events where several stalls are set up to sell food from different cultures and jewellery or products from the culture- kind of like a mini flea market. It is quite busy in summer!
However, the mall itself is usually empty and there isn't a lot to do there. They have a few restaurants inside and a couple of fastfood stores but usually there is not a lot of people. They also have a Second Cup and Starbucks nearby.