The Theory of Leech Computing
Phil Frisbie, Jr. writes "I am defining Leech Computing as 'a program running on a client computer without user knowledge that can process data and report back the results, but otherwise does not effect the usability of the client computer and makes no changes to the client'. Leech Computing, Part 1 covers basic theory."
There's also a good page quickly discussing Villain-to-Victim computing. The point is to use correctly configured machines to do things they were not intended to.
I recently ran Ad-Aware on my windows box and was surprised to find there were 4 spyware programs installed and running, and remnants of 3 more existed in the registry. And I thought I was being careful...
Somebody please tell this machine I'm not a machine -