Jesper Rønn-Jensen is planning a suicide mission on December 15th. He's going to turn off all spam blocker on his blog, just to see what happens. He's also inviting everyone to join in.
When I first got to know about that, my first impression was "what a stupid idea". But curiosity killed the feline and I had to go through the entire post.
The main idea behind this is to find out how much work Akismet and other software save us. Not to mention server load.