I don't see any previous mention of this here, but here is a news story that sounds intriguing;
http://news.bbc.co.uk/2/hi/science/nature/6146292.stm
Esentially a red rain falling over part of India back in 2001 which has promted some interest:
quote from article:
"Not only did Dr Louis discover that there were tiny biological cells present, but because they did not appear to contain DNA, the essential component of all life on Earth..."
Anyone know more about this?