I have this cooking website I started some time ago (http://cookarr.com), and apart from that I have some smaller projects, but I also say "No, I don't have side projects except of these, I don't have to do open source, I just... don't". It never did sabotage my interview though, because I am a specific kind of full-stack developer (good at prototyping and whipping up complete "MVP production apps" in a short time), and it's somehow valuable to many startups.