Here are all the current codes I could find. We rented one today (Cloudy with a Chance of Meatballs) and are about to put it in, which reminded me to post the codes!!
Redbox: ACME25 or DVDONME or BREAKROOM
Blockbuster Express: KIOSK (expires 2/10/2010) or GT11A (expires 1/31/2010)
Each code can be used once per credit or debit card.
Can’t beat a FREE MOVIE for Family Movie Night!