Ram Dass wrote and said some interesting things about LSD in his books and talks, and had a unique perspective, as an ex-psychology professor and Hindu guru. He gave his guru in India a very large dose of LSD and the guru said "Enlightenment has come to America in the form of a pill."

Personally, I tried (what I think was) LSD a few times, mushrooms a half dozen times; in short, it was the most amazing thing I've ever done. Super-highly recommended. Mushrooms especially, as you know what you're getting. Do it with someone who knows what they're doing and you trust.