I have lived in downtown, Calgary for a few years now, so the Olympic Plaza is a place I frequent on occasion.
One of the best things about it is that it almost always has one interesting event or another going on there. Rob & I have been to a variety of cultural events there, like Latino days, and a Reggae festival...those are days when it's fun to splash around in the water while listening to the live bands. In the winter, the water doubles as a skating pond for those of you who enjoy ice-skating ;)
The Olympic Plaza really comes alive during Stampede week too, as they have free pancake breakfasts and even line-dancing going all up Stephen Avenue.
Oh, and did I mention this is also where we got engaged? If you can, come check out the New Year's Eve events here, as they are child-friendly as well. Dress warmly though :)