I also have a movie recommendation, "Pi". It's not sci-fi strictly speaking, it's more of a mathematical thriller, but it scratches the same itch. Here's a plot summary I nicked from IMDB:
In Manhattan, behind six locks, lives Max Cohen, a mathematician and computer whiz. Since staring at the sun at age six, he's had terrible headaches; plus, he can't abide human contact except with an aging professor, and he's obsessed with finding numeric patterns. His current obsession is the stock market; his theories bring him to the attention of Wall Street traders. He also keeps running into Lenny, a fast-talking Hasidic who fronts for a cabal that wants to rediscover long-lost mathematical mysteries in the Torah. Neither group is benign, and they pursue Max as his hallucinations and headaches worsen. Does nature offer any solutions? Can Max find them?
I do offer one caveat: The movie is in black and white and cost about ten bucks to make, and it looks it. So if grainy film and poor production values bother you, it might not be the movie for you.