Here's a funny one for you. My mom's hair went from grey to brown...only it wasn't the hair on her head! She started dating a virile man 16 years her younger and within months - and after 18 years of not dating at all - it turned brown!! I'm serious.
She never figured out how to get the hair on her head to work the same way, but man was that funny! She has since dumped the boyfriend. I haven't inquired as to the current status of her folicles.