#3 – Primer
Shane Carruth’s 2004 directorial debut (he also wrote, scored, edited, photographed, and starred in the film) starts out with four men in a garage who may or may not have made an amazing scientific discovery. From there, things get increasingly complex. Even if you can cope with the explanations of the way the “box” that the men created works, the explorations of trust, morality, and consequences take the movie down some mind-boggling paths. There are several graphs available online to explain some aspects of the movie, if it helps.
Primer was a small, independent movie that went on to be hugely popular. If you have time to watch the film and then spend a few hours debating it afterwards, you should.