Wow, I was totally blown away earlier this week when I started listening to a book on CD titled "The Mystical Kabbalah". If you haven't heard of the Kabbalah before, it is the "mystical aspect of Judaism".
What blew me away was listening to the first five minutes of the CD, I couldn't tell if I was listening to a talk on Zen, Yoga, Sufism, or even Shamanism. The author himself goes on to say the exact same thing just a few minutes later.
It's amazing to me that groups of people with different religious beliefs that have been spread around the Earth have all come to nearly the same points regarding meditation and awareness when they really try to get to the root of existence. Their approaches vary a little bit (IMHO because of their prior belief systems), but as I continue to listen to the book on CD, the author's discussion of the Kabbalah has tremendous parallels with Zen, including meditation, awareness, and even a story about flowers and mind-to-mind transmission of thought, which remarkably parallels the Zen story of the transmission between the original Buddha and the First Patriarch.