Not in the same genre, but another cerebral film I like to watch every so often is "The Fountainhead" -- 1949 with Gary Cooper and Patricia Neal. Yes, it is a film adaptation of the Ayn Rand novel, the scene play written by her. I am transfixed every time I watch Howard Roark's speech in the court room scene. I've been tempted to memorize it, settled for transcribing it myself. If I ever get around to having a personal webpage (something I've considered since the late 90s) it would definitely make an appearance.
“Extinction is the rule. Survival is the exception.” -- Carl Sagan