A great site for reading about reported ghosts and hauntings in Toronto (and the rest of Ontario) is Toronto Ghosts & Hauntings Research Society.
In their Toronto public buildings section you can read ghost stories about the Mackenzie House, Casa Loma, the Royal Conservatory of Music, Lower Bay Station, the Old Don Jail and about 40 more.
Speaking of Toronto ghost stories, this seems like the perfect day to refer you all to my favourite Toronto ghost story of all. Will Ivan Reznikoff strike again?
Happy Halloween!