I recently read the book _What The Dormouse Said_, which is about the early days of silicon valley computer culture and the interaction of that culture with the counter culture.

According to that book, there was a notable portion of the people in that early SV culture who at least experimented with LSD, and there was even an organization called the "International Foundation for Advanced Study" in Menlo Park that was founded by an engineer to study the possible benefits of LSD use among engineers.