Brooklyn based artist, David Horvitz fils his time with photography projects and has found a nitch specifically in social experiments.
1. Once he used google to find random fax numbers in different citites, looked up when sunset was in each city and faxed it randomly around. 'Today the sun will set at 5:45 pm' He was hoping this would interrupt someone's daliy routine and encourage them to go watch the sunset.
2. If you give him $3 he will send you an empty envelope. It is like sending you nothing. Or at least, it is sending you something that has traveled a journey that is the distance from him to you. (he has all sorts of projects like this one) http://www.davidhorvitz.com/if/