You could simply print out a QR code requesting X BTC (X being the ticket price)
People with bitcoin scan using their phones, then hit send. You could have a PC running the client with Bitcoin-Qt open. It would post the transaction in under 3 seconds and then they could be given the paper ticket even with 0 confirms(The chance of an invalid transaction is currently 1/10,000). By the time the movie is over, you'd have the spendable bitcoin in your wallet.
Sell the coins on localbitcoin.com if you want the local currency.
The people working in this cinema are artistic souls who have problems using a computer. It looks like I will do the charitable work and:
a) will sit there for a month with my laptop
b) will generate QR codes using Bitcoin-Qt based on BTCPLN rate of exchange on MtGox, and then
c) after receiving payment in Bitcoin, I will be putting Polish currency into the cinema cash register
untill a better option is found
EDIT: There is a free WiFi in the cinema. Maybe WiFi could be used somehow to facilitate Bitcoin payments.