One problem with freelancing is it seems most of the jobs are either php or ruby. I've been working with .NET, javascript, coffeescript, and SQL the past few ye

One problem with freelancing is it seems most of the jobs are either php or ruby. I've been working with .NET, javascript, coffeescript, and SQL the past few years. I'm very good with those and can do every aspect of an app. Looking on careers.stackoverflow, and craigslist, .NET jobs seem to be pretty rare in the bay area. What would you recommend I learn if I want to work about 20h/wk there? Ruby? PHP? And which framework(s) (RoR, Cake, etc)? Another option I've been toying with is using Xamarin to leverage my C# skills to build mobile apps. This is something I'm going to probably be doing anyway. Would I be able to get part time or consulting work doing this? Or is it too niche? I thought I'd build a handful of apps between now and then to try to make a little side money, and then start doing contract work with those skills.