Tron is a movie from the 1980's starring Bruce Boxleitner and Jeff Bridges, in which a programmer is "digitized" and descends into the computer world, to fight against a despotic MasterControlProgram to free his company's mainframe.
This film was one of the first to use extensive computer graphics. Its style is very distinctive.
It also demonstrates a remarkable knowledge and appreciation of computers. While its representation of programs and the computer world is fanciful, it respects the way that computers really work (particularly when showing the real world). Considering Hollywood's track record for showing computers, this is a reasonable compromise between the reality of things and action/adventure fantasy.
I think this is because the film is early enough that the people doing the graphics/computer bits would also have been programmers, not Photoshop jockeys
"Geeks" tend to appreciate this film a lot (which is why this page is arguably on-topic for this Wiki).
Tron invented the ever-cool LightCycles?.
Tron 2.0 was released as a computer game, although a screenplay was written.
Tron fan sites include: http://www.tron-sector.com
The sequel, Tron Legacy, came out in December 2010.