This happens a few times a year.
Today December 6th through December 8th 2013 you can go to an Sams Club nationwide and shop without a membership card. You will pay member prices.
The Facebook page mentions its in store and online, but ive not tested online to confirm this
"Open House. Friday, December 6 at 11:00am in CST ... Shop in-club or online now. http://samsclub.co/0xSBF6 "