Enigma (IMDB) (Netflix)
The Allies' theft and use of Germany's Enigma code machine, without the Germans ever getting wise, almost certainly determined the outcome of World War II in Europe. It also provides the backdrop for this romantic period thriller about cryptography, counter-espionage and near-obsessive love. This is a complex puzzle set that requires audiences to listen closely to put it together, and to appreciate the Tom Stoppard dialogue (much like watching a baseball game, if you're just waiting for the ball to be hit, you'll be bored out of your skull, but if you can focus on the pitch-by-pitch duel between the pitcher and batter, there's all of a sudden a lot going on).

The suspense never quite pulls you to the edge of your seat, and there's a Hardy Boys/Nancy Drew-story-with-consequences feel that other directors might have avoided, but it's still a pleasant enough ride for history aficionados, Anglophiles and mystery fans. Dougray Scott (the lead heavy in Mission Impossible II) is the code-breaker and jilted lover at the end of his tether, and Jeremy Northam (the actor/singer/pianist in Gosford Park) gets most of the juicy lines as the spy-catcher. Kate Winslet is the plucky under-appreciated code clerk who befriends Scott, and Saffron Burrows is the heart-breakingly beautiful cipher whose disappearance pulls Scott into the mystery. I have no idea why it's rated R in the U.S.; seven-year-olds can see it in Sweden. (For a great novel about cryptography, try Neal Stephenson's Cryptonomicon.)