While stumbling some sites recently I came across
The Age Project. It's free to join. All you need is a username, password and email address. During registration, you're asked to upload a photo (pick a good one please). You're all done. Now just wait on visitors to the site to guess your age. I've always been amazed at how people lie about how old they think you are. Maybe it's to avoid hurt feelings or to boost your ego. Either way I think the truth is always best. I'm anxious to see what my average age will be based on what visitor's think.
