This is one of the most bizarre, fucked up movies I've ever seen. The premise is absolutely bat shit, bone chilling... and it's mind blowing to realize it actually happened. That a guy could be that sociopathic and pathological. That a family could be that fucking naive and stupid...but it's Texas we're talking about. It's pretty awesome the approach the filmmakers take with this documentary, making it more of a docu-thriller, complete with 3rd act twist. It's a wholly unique experience and one of the best films of the year.
The Imposter 2012
I actually saw this on a really really bad date I had earlier this year! Going to have to echo your sentiments and say the movie portion of the date was well worth it. The story is so mind-blowing I was surprised it hadn't been turned into a movie until this year. My only complaint is that I could have done without some of the reenactments. It made some of the film feel like an episode of Unsolved Mysteries or something. Would've preferred that it was just a straight documentary.
Edit: Just realized this was probably the best film I saw in theaters this year and I totally forgot about it until seeing this thread. I never bother making top ten lists but if I did The Impostor would very likely be number one for whatever that's worth.
I'd argue that's what made it a unique experience.