I know this deal has been posted in the past, quite some time ago, but I thought it was worth reposting, especially since it is coming to an end next week.
The MBNA rewards web site allows MBNA cardholders to purchase gift vouchers for major high street stores and some online retailers including Amazon.co.uk with savings of up to around 10%.
Minimum spend is £100 for most voucher types. However they have discounts on cinema tickets too, which you buy as a pair.
Some examples of savings:
Edit: Updated link, password is mbna