A few months back, I blogged about GalaxyZoo, a very cool project that lets anyone classify galaxies from a professional astronomical survey of the sky. They got thousands of people helping, and have classified a million galaxies.
But they had a problem: people were finding significantly more counterclockwise-rotating spiral galaxies than clockwise. That's a problem! We'd expect the numbers to be almost exactly the same. Did the GalaxyZoo folks stumble onto a new and previously undiscovered cosmological property?
Turns out, no. It's not in the stars, it's in ourselves. I interviewed astronomer Chris Lintott from GalaxyZoo, and he explains it all.
They have this on their blog as well.
By the way, here is an image to help you understand the CW versus CCW rotation problem:
Hope that helps. :-)