All The Burgers You Can Eat
These days most restaurants have apps where they try to attract more customers by including coupons or fun games. This particular burger chain had a “roll the dice” game to get a code for a free burger upgrade. The catch was you could only try it once a day and the date even appeared on the code so that the cashier could verify it.
The OP however discovered a loophole whereby you could try again immediately just by changing the date on your phone and keep at it until you got a code. It worked like a charm and he got free burger updates for years. Brilliant!