We are living in a golden age of self-expression. The explosion of user-created content on blogs and social networking sites movedTime magazine to name "You" their 2006 person of the year. But while we may be spending a lot more time in virtual worlds, we have not lost the urge to make our physical world more meaningful. By leaving art and ideas in public places, you can affect someone's daychange their mood or their mindand maybe even change the world in the process!The Guer