If you need to buy Canon EF and/or EF-S Lenses, Canon has launched a big Buy MORE, Get MORE Lenses. You have to buy two (or more) different lenses to qualify for this offer. For example, getting a 50mm f1.4 and a 85mm f1.8 qualifies, but getting two 50mm f1.4 does NOT.
When you do that, you have to submit the mail-in rebate to Canon [PDF file], and a few weeks later, if all is well, you will receive a prepaid American Express Gift Card. I am not sure exactly how the Bonus amounts are calculated, they give a couple of examples but no formula. Promotion ends 4/29/17.
For more special offers, check the long and winding Canon USA Special Offers page.