Ram Dass (formerly, Dr Richard Alpert) is the first guy in the video. In the early 1960s, he was Professor in Psychology at Harvard. In 1963, he was fired for his involvement in psychedelic drugs research. In 1967, he met Neem Karoli Baba, studied under him for several years, then returned to USA. He authored an influential book: Be Here Now (416 pages, 1978), which was published with Baba's permission. An incident pertaining to the publication of the book is recounted here. The LSD Episode with Neem Karoli Baba is mentioned in several books and articles, for example, in the book Miracle of Love: Stories about Neem Karoli Baba (414 pages, 1979).
Bhagwan Dass is the second guy in the video. He introduced Ram Dass to Neem Karoli Baba in 1967.
Larry Brilliant, a good friend of Steve Jobs (co-founder of Apple), is the third guy in the video, appearing at 4:59. Larry Brilliant's life story is fascinating — read this interview. Other than being a student of Neem Karoli Baba, he led the team that eradicated small pox in India, he did tech startups and he even headed google.org, the philanthropic arm of Google. In this video: Neem Karoli Baba and Small Pox Eradication (YouTube) (audio quality not great), Larry Brilliant narrates how Neem Karoli Baba predicted that he would become a UN doctor who would help eradicate small pox in India. Another interview in which Larry Brilliant talks about Neem Karoli Baba from 18:51 to 20:25. Larry Briliant on Sewa Foundation (YouTube) is another good video.