When I started my meditation practice, the guided meditations in the Calm app  helped me a lot.
In essence this book tells why secular Buddhism (secular, western meditation) is actually a very reasonable way of spirituality.
If you're looking for consciousness expanding activities, I found my meditation practice and buddhist readings were 1000x more powerful than my drug attempts. For an HN'er I'd recommend starting with this:
as its more sciency/modern than diving into the Pali Canon or popular but dated 1960s attempts to westernize Buddhism.
Fresh book recommendations delivered straight to your inbox every Thursday.