Do you need to use your Flex Points? The Shack is having a 15% - 40% off sale all of this week. This sale excludes smoothies, coffee, and grab and go. Some other exclusions may apply. Shack Hours: Monday - Thursday: 7:00 a.m. - 5:00 p.m. Friday: 7:00 a.m. - 4:00 p.m.