I like to imagine lots of people tripping and going to this movie because of the light show they heard about, but the part that really blows their mind being the whole sequence with HAL 9000.
I was 8 years old when I saw it -- no movie has influenced me like that one. At that age, the star gate scene was kind of scary; but, yes, the HAL 9000 had a _huge_ impact on me. One of the best films, ever.
Having only seen in on TV (multiple times) I saw the 70mm version at a local cinema recently. Amazing experience, and it holds up remarkably well IMHO.
https://www.youtube.com/watch?v=1DNbkKBW0K8