[img]http://blogs.palmbeachpost.com/malled/files/2009/01/redbox.jpg[/img]

If you're American I'm sure you've seen a Redbox kiosk around. They're everywhere anymore. I found this site with a list of promo codes that Redbox sends out for free rentals.
[url="http://www.insideredbox.com/redbox-codes/"]http://www.insideredbox.com/redbox-codes/[/url]

I used the DVDONME one and rented Moon for free from a Walgreens kiosk today. They only work for one day rentals and you can only use a code once with a certain debit card. If you have three separate debit cards and one code you can score three rentals for free.

The site is supposed to update as new codes come out.