"What's the link between the lottery and cinema?", is something I know you've not asked and don't care about. Let me tell you. The National Lottery funds the British Film Institute (BFI). The end.
The BFI uses the National Lottery's funds to "develop and support original UK filmmakers and films" and the lottery is happy to let you know that without its generosity, "films like Bend It Like Beckham, The Kings Speech etc wouldn’t have been made." A bold claim, but alright.
Over 250 cinemas across the country are participating in this weekend's promotion. All you have to do is buy a ticket for the Lotto Double Prize Event Draw tomorrow, August 24, and you can claim your free ticket to be used on Sunday, August 25.
You can find the list of which cinema chains are taking part over on the Cinema Day website, but it includes the ODEON, Picturehouse, Empire, Light, Merlin, and Picturehouse.
Tickets are limited to 500,000 and once they're gone, everyone will be added to a waiting list for cancellations, because we all know how considerate customers are about letting venues know they can't make it, as opposed to just not showing up without telling any bugger, for example.