Red State is a great movie. It’s about an extremist religious group killing people and a resulting standoff between them and government agents. The group is similar to the Westboro Baptist Church, only with more murder and lots of guns.
I found it to be totally unpredictable and full of surprises, which is rare in my experience. It was also pretty thought-provoking. At the end, I wasn’t sure who the real enemy was.
It’s extremely violent and pretty gory at times, but if that doesn’t bother you I definitely recommend it. It’s available for streaming on Netflix.