RedFive said:

I don't know a single 8 year old who would sit through ten minutes of that movie, let alone the whole thing. For that matter, I don't know a whole lot of adults who would either. A lot of people go to movies to relax and be entertained, not to use their brains, and while I'm sure the case was the same back then, in 68 those effects would have been highly entertaining to those who didn't care about the rest of the movie. It's too bad there aren't a lot of smart movies today that are also big budget extravaganzas.

I saw 2010 for the first time a couple years ago. Just terrible.

You are aware a certain segment of the audience was consuming something a little stronger than what you could get at the snack counter while watching the movie back then? ;)

The making of 2001 paperback mentions the incidents where someone in the theater got a little too deep into the film!