When friends come to visit Toronto, this is where I take them.
There's no question that Harbour Front Centre is a microcosm of everything Toronto has to offer.
First, it's beautiful - right on the lake. If it's the summer, the canoe / wading (you might get yelled at) pond is open. If it's winter, there's a skating rink. All season long, there's the lapping waves of the lake.
Second, it's full of art - be it the glass work displayed in the fabrication hallways, or the rotating photo gallery, or the open space which has free exhibits all year long.
Third, there are always events going on - multicultural festivals, author's reading, theatre... and a great number of these things are free (be sure to ask for a programming guide to check out what's coming up.)
Fourth, the gift shop - there are items here you normally wouldn't see outside of internet shopping sites.
All in all, it's a great way to spend an hour, as you make your way along the beautiful Toronto Waterfront.