Trivia: The Computer Science department at the Engineering School at the University of Illinois in Urbana, Illinois, have a "birthday party" for HAL every January 12th - the date & place HAL became operational in the movie.
Trivia: Both director Stanley Kubrick and author Arthur C. Clarke originally chose Jupiter as the Discovery's destination, and production of the Jupiter sequences and elaborate special effects were already finished ("in the can") when Kubrick abruptly decided to change the destination to Saturn. Kubrick thought Saturn with its rings would be more visually exciting than the Jupiter footage that he had already finished, so he ordered his special effects team to begin work on the Saturn effects. At the same time, Arthur C. Clarke changed the destination to Saturn in his "2001" novel that he was writing concurrent with the movie's production. Stanley Kubrick was well known for making such sudden and costly changes in the middle of production, but money wasn't really an issue; in fact, when Kubrick showed MGM studio heads and investors his early special effects footage, they were so awestruck that they all agreed to pay any price for the finished film. The real reason that Kubrick didn't go to Saturn was the protest of his exasperated special effects team, who had spent an enormous amount of time and effort on the already-completed Jupiter footage and had stretched their ingenuity to the point of exhaustion. The FX artists and technicians were extremely proud of their work and argued against simply discarding it to the cutting room floor. Kubrick, in typical fashion, abruptly dropped the Saturn idea without a second thought and stayed with Jupiter. (Strangely enough, Arthur C. Clarke still thought Saturn was a better destination, so he kept it in his novel, which published shortly after the movie premiered).
Trivia: There is no dialogue in the first 25 minutes or in the last 23 minutes of the film.
Trivia: The scene where Bowman is shown floating through HAL's 'brain' prior to disconnect used a stunt double in a space suit suspended by wires behind him. During one take the wires failed, dropping him to the floor and causing serious injury.
Trivia: Almost every company whose product was advertised in this film is no longer in business.
Trivia: Not only "Echoes," but also the album "Dark Side of the Moon," less the songs "Money," "Us and Them," and "Any Colour You Like," can be perfectly synchronized to the Stargate sequence.
Trivia: Originally the film was going to end with the Starchild activating the nuclear launch platforms orbiting Earth, using the planet's destruction as a means to accelerate the evolution of mankind into its new universally intelligent form. Stanley Kubrick eventually decided against this as it was too similar to the ending of his previous film "Dr. Strangelove".
Trivia: To film Dave Bowman's explosive transition from the pod into the Discovery, a vertical airlock set was constructed. Keir Dullea was suspended on wires and pulled to the top of the set as the camera shot upwards from below. This, combined with the establishing shot of the pod lined up with the airlock door, gave the illusion that he was floating horizontally into the ship - the wires suspending him from the ceiling were hidden behind his body.
Trivia: People speculate that HAL is a reference to IBM, as the letters differ by one position. Kubrick says this is a coincidence, but was concerned about IBM's reaction to the film's references, including the IBM logo on Bowman's spacesuit. However IBM had no problem as long as they weren't associated with the "equipment failure," or listed as technical advisors for the computer.