Through Saturday, July 13, Denny’s is shaking up their menu with a cool BOGO offer at participating locations. Get a FREE milk shake (of equal or lesser value) with the purchase of one. It’s the perfect opportunity to try one of its new flavors – Strawberry Cheesecake, Blueberry Cheesecake and Lemon Icebox Pie. The discount requires this coupon and is not available with any other offer. For locations in Colorado, click here.