Great reading: A Secular Society (from the Orthodox Christian Education blog). Highlights:
1. WE DO NOT ALL HAVE THE SAME GOD.
2. SPIRITUAL EXPERIENCES ARE NOT ALL CHRISTIAN.
3. NEVER JOIN IN FOR THE SAKE OF WORLD PEACE.
4. SIN HAS BECOME FASHIONABLE.
5. NEVER ACCEPT AN INVISIBLE MARK.
Under #2 - "Today, it is popular for many to seek out experiences of hypnotism, meditation, yoga, horoscopes and fortune tellers. These are all ways of opening ourselves up to spiritual demons that can do great spiritual harm to our souls. At first, they seem harmless or even holy and divine, but this is how we are tricked into participating, and later the darkness of these experiences will be made known. Some even go so far as to suggest that the Holy Spirit transcends all faiths - this is blasphemy. The Holy Spirit was given to the One Church established by Christ, and those outside of it, cannot be in communion with It."