ACME25 to get a free one-night movie rental with at your local Redbox.
Other codes that are may still be valid:
DVDATWAG (works only at Walgreens locations)
And the first Monday of each month a code is released that's valid for a free movie that Monday only. You can sign-up for text messages here to get a unique code for your free movie that can only be used once and it is unfortunately not shareable. Just yours.