You should be able to get a free movie rental tonight only (10/28) courtesy of Redbox.
The code to use is LTYN674T.
I actually already picked up a movie myself and it worked fine for me but just to be certain you can reserve your movie online first. Enter the coupon code at checkout and the price should drop to $0.
Here is how it looks:
Remember you do need to return the movie tomorrow or you will be charged for a night’s rental.