The 419 Flash Mob is attempting to recruit as many people as possible to launch denial-of-service attacks on spammers' bandwidth and report them to their Web hosts and to legal authorities.
I wonder how legal their tactics will be. Depends on the country's laws I guess.

http://news.zdnet.com/2100-1009_22-5571061.html

http://www.aa419.org/flashmobs/current-mob.php