I am doing this now. I work full time and spend another 10 - 20 hours per week doing work for a startup as a contractor. The other contractors I work with are a

I am doing this now. I work full time and spend another 10 - 20 hours per week doing work for a startup as a contractor. The other contractors I work with are all on opposite side of the world time zones so it's a bit difficult to communicate. I end up working really random hours, 6 - 9PM, 10PM - 1AM. I'm not sure how common this kind of work is but it has been going well so far. I think the key to my situation is that the company is local to me (I live 2 blocks from their office). I only go to the office once or twice a week for a couple hours and I am the only contractor that is local.