A pioneering work of Science Fiction and one of the longest running TV series ever. It revolves around the lives and work of FBI agents Fox Mulder, a conspiracy theorist and believer in aliens, and Dana Scully, a non-practicing doctor who is often exasperated by Mulder's paranoia. The two agents are assigned to cases involving the unexplainable and the paranormal. Episodes have involved the whole gamut of plot themes, from Time Travel to Shapeshifting to Ancient Jewish Mysticism. Part of the show's allure is that the episodes rarely have what can be considered a "happy" ending, but one that does usually bring closure to that particular case.
The theme music for the X-Files is so creepy!