This is Dundas Square. It's on the southeast corner of Yonge and Dundas. Right across the street from the Eaton Centre and south of the recently built Toronto Life Square (2007).
In a past life it was a block of old commercial buildings. Sometime in the mid-90's it was decided the city needed a new public space and in 1998 the Toronto City Council expropriated the land for such a use. Designed by architects Brown + Storey Dundas Square became a reality by the end of 2002.
Surrounded by many bright lights and giant billboards it's been called Toronto's version of a mini Times Square. Among it's many uses it's been the site of concerts, film screenings and other public events. During the summer you can find many people, visitors and locals alike, lounging about enjoying the weather.