Luis von Ahn recently gave a Google Talk about his ESP Game, which is a way to get people to label images and thus make them easier to search for. Google is now trying the idea at http://images.google.com/imagelabeler/
Google Blogoscoped found the Google version, while Danny Sullivan at Search Engine Watch spotted the connection to Luis von Ahn and posted the video of his Google Talk. It's well worth watching if you have an hour to spare.
Comment: The Google game suffers from the pictures being too small and from many of the pics being either unreadable or boring. We're not talking about great examples of photographic art: the Google game often throws up graphics and odd bits of artwork, which may not be the sort of things you'd look for when you use image search.
