Last week, I interviewed Bob Jacobsen for FLOSS Weekly. Bob used Perl's Artistic 1.0 license on some Java code to manage model trains. The code was later patented by an Oregon-based company(!) and then Bob got sued(!!) for Bob distributing the other company's patented code(!!!). The good part of the story is that this is the first test at the US Federal Appeals Court level for an open source license to be enforceable even if no money exchanges hands, and... we won!
Bob spent a lot of time and money on the case though. Listen to the podcast and contribute to his legal defense if you care about open source.