Head to Redbox and use promo code SWEET to get a free DVD rental through (2/14). I got an email with SWEET and have seen it "out there," so it should work for everyone.
I've also seen HEART will get you a free rental.
I'm not positive about that one or when it ends.
If you want two, give it a try, but no guarantees.
You can also reserve a movie and it will be waiting for you.
Then, you can use the code at the box when you are checking out.