Yep. It was more than 30 years ago that I heard his theory, my dad read the book. One thing I appreciated about it was that it opened my mind at an early age. But there is enough hokiness in the theory for it to be discarded, mostly.
Some of his stuff is VERY intriguing, though. For instance, I think he was the first to point out that all the ancient calendars had 360 days. His premise was that it wasn't that they couldn't count but that the earth took 360 days to revolve around the sun at the time. I wonder if he was onto something. So I keep my ears tuned to stuff that might have bearing in his theory and keep mulling it over...
When I look at both sides of Van Danniken's theory, I see he was pretty full of horse manure. There was a great video that rips his theory to shreds, I can't remember the name of it.
I don't think that ALL of them had 360 days, but for many of the older cultures in the middle east (until finger-counters took over), base 12 was used, and by derivative, 60, and 360 were common units. 360 degrees in a circle, 360 days.