the big german online shop AC-Foto does, as last year, a advent calendar "promotion".
Every day, some article(s) are drastically reduced in price. Last year it was almost exclusively canon gear. All the high end stuff could be had for considerable discounts (1D series, 5D, 6D, all the supertelephoto lenses, etc). Sometimes also other stuff like backpacks is reduced.
Today they started off with massive price reductions on the 300 2.8 II and the 500 4 II (reduced by 1349 and 1249€, respectively!)https://www.ac-foto.com/onlineshop/v3/?s=advent
and no, I'm not affiliated with them^^
But if you are looking for some specific canon gear that might be your chance (crossing my fingers for the 16-35 III)