Recently, I came across an awesome racy band called Hexentanz (literally 'Witch Dance'). They're playing so-called ritual ambient. Their music represents dark soundscapes, filled with ritual sounds and hypnotic drums that take you away back in the medieval times. It's composed with actual instruments of that period, synthetic ritual devices, and even with human bones. Lyrics are more like arcane chants dedicated to witches and occultism. Believe me, it's worth listening to.
http://www.youtube.com/watch?v=iA9SgN53yKY
Hasch tobira hasch du kan hier forto hasch ti konta
It was the Erythraean Sea the Mother Serpent found
and from the caves shall she be called
unto the sabbat enthroned on the Elder Oak
does the dragon coil around