I am sure everyone knows about Meerkat Movies. However with a couple of tweaks and some planning the savings can be further improved.
Each November/December Showcase has reduced the costs of its gift cards. If you buy in the denomination of £100 it costs £75. Combine this with Meerkat Movies and the NUS student card trick (available to all) and you can get two people to the cinema on a Tuesday or Wednesday for about £5.