Blockbuster is doing one of the more interesting promotions that I've seen.
If you use the Netflix, you can bring in your shipping label (the part you usually throw out) and get a free rental from Blockbuster.
Obviously, they are trying to get you in store and interested in the Blockbuster service, but I did personally get a few free movies today.
If you use Netflix, this is going on until December 21st.
http://biz.yahoo.com/prnews/061205/datu010.html?.v=83