I always go to the Book Depot Warehouse (Welland Ave., St. Catharines) for their annual 50% off everything in the store Boxing Day sale (everything except their Melissa & Doug products). Their prices are already about 50% less than retail list prices so, with an additional 50% off, it's worth getting up early to be there at 9:00 am when it opens. ;)
DH and I went earlier today, before the snowstorm hit, and left with 5 boxes of AMAZING deals!