Have you gotten an interview based on your open source contributions?

Yes. The interview was a all expenses paid week long trip to another country, with a couple dozen other contributors, to hole up in a hotel and hack on the project, with a few organized tours as breaks. Based on that, the company made me a job offer a few months later, which I declined, largely because I wasn't looking for another job. So they hired the company I worked for to have me do some work for them.

The recruiter that brought me to the UK from Romania found me by using some weird github search project that told him I was one of the top ruby developers in the country, based on stars I had on some open source redmine plugins I worked on at my last job. Pretty wild when I think about it now.