Just got an email from blockbuster with a link to this Golden Ticket which gives you 6 movie or game rentals for £4.99 which can be used anytime before march.
Also if you redeem it before 2010 you get an extra rental.
Considering game rentals are like £5.95 for new release games that works out to:
7*£5.95 = £41.65 worth of rentals for £4.99
saving of £36.66
game rentals now £6.25 each 7*£6.25 = £43.75
saving of £38.76