From my understanding, Spirit Science is a very silly ploy for the writer or publisher or whomever it is to make money. Also, while it may be entertaining at times, there isn't really much proof to back it up. Now as an epistemological solipsist, I can't really say that all this stuff is "true" or "false," but one has to think that a lot of times people blatantly make things up for personal gain (e.g., Christianity). Also the Nexus loves evidence and scientific inquiry!
Stemming from that, I do happen to enjoy Peter Joseph's Zeitgeist (and its exquisite and acute portrayal of modern religion), and I especially like how the companion handbooks and what not are totally free. Anytime there is money involved in something, I doubt its authenticity. But Zeitgeist is really all about (or so it seems to me) moving the world to a happier, resource/bartering based economy. While I agree that this would be nice, it is by no means practical nor currently possible. One also must admit that some people have grand visions for the planet, many of which are quite delusional. However I admire him for spreading his message, and possibly changing some minds/lives with his movies and books.
As far as sacred geometry, it's very cool and beautiful. I have some paintings of it in my bedroom, and I love sacred/spiritual/visionary artwork. Does it speak to deeper truths within the universe? Maybe for some, but I would say that it is impossible to say definitively for all at this time.
I like how all of the things you brought up are part of "alternative" culture (i.e., outside mainstream thought). I am sure that many Nexians have read about these types of things. On a deeper level, I find that much of it is about digging deeper into life and what could possibly be out there rather than participating in the daily grind. So thank you for sharing.
"Think for yourself and question authority." - Leary
"To step out of ideology - it hurts. It's a painful experience. You must force yourself to do it." - Žižek