Danish Films: Flickering Lights, The Green Slaughter, Adam's Apples. Might be slightly misspelled due to the translation. If you can't find those titles, try Blinkende Lygter, De Grønne Slagtere, Adams Æbler.
Oh, I've heard of Adam's Apples, a German movie site comparable to last.fm says I could like it. I'll check it out.
»Das Experiment« is a great German movie by the same director who made Downfall (also a great movie). It's based on the Stanford Prison Experiment. There's also an American remake, but I haven't watched it yet.
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The discreete Charm of the Bourgeoisie« also seems to be a very good movie, unfortunately I've only watched half of it but it's still on my list. It's about a group of people who try to dine together but fail for various reasons. Strange but interesting film from Spain/France.
Also, I second »
The lives of others«, a German film about the GDR, especially the Stasi.