Tron 2.0 was not a hit by any stretch of the imagination. Released in 2003, it was well-reviewed, but didn't catch on with gamers; Tron fans in particular, at least those that I know, seemed to have a particular dislike for it. I, on the other hand, was a big fan, and so I'm very pleased to see that it's taken its rightful place in Disney's recently-launched Steam stable.
The game is really only loosely connected to the movie: Bruce Boxleitner reprises his role as Alan Bradley, but the action focuses on his son Jethro, aka Jet, who is digitized by his father's AI to aid in the fight against the runaway virus Thorne. It's a fairly conventional shooter, but the expected Tron elements are all here too; the disc weapon made famous by the movie is present and actually quite useful, and you will also race light cycles—although you'll be forgiven if you choose to skip those bits, since they're almost impossible to beat.(Monolith, the developer, actually patched in an option allowing players to get past the light cycle segments without winning them, because of all the complaints from players.)
Despite not having much to do with the film, it's all wonderfully Tron, with clever dialog and everything rendered in neon, including your stretchy duds. And the gameplay, light cycles notwithstanding, really is quite fantastic; as far as I'm concerned, it's a shamefully underrated game. Fortunately, it's also really cheap: Tron 2.0 goes for $10 on Steam, and for the next couple of days is can be had for ten percent off.