Patent Trolls
"Patent trolls don't make products. They make lawsuits. They buy up the ridiculous patents of failed companies and sue the everloving hell out of everyone they can find, building up a war-chest from easy victories against little guys that can be used to fund more serious campaigns against larger organizations. Since there are no products to disrupt with a countersuit, there's no mutually assured destruction."
(http://www.informationweek.com/news/showArticle.jhtml?articleID=197003052&pgno=2&queryText=)
More Information
You may get help from the Electronic Frontier Foundation's Patent Busting Project at http://www.eff.org/patent/