By "something," what exactly are you looking for? I'm just curious.
It's very difficult to contribute open-source work outside of a day job, especially when you're working on your own side business. The best I've accomplished in the past is getting my employer on-board with the idea of contributing back to open-source for 50% of my time. That's a lot easier at a start-up, however.
I've been there. Still, I'd want a code sample anyhow.
If open source becomes the dominant mode for hire screening, it provides an interesting disincentive from taking jobs at open source unfriendly companies.
I rarely hire anyone without it these days.