Above all else, it should be fun. If your son finds programming enjoyable, everything will fall into place. For that reason, I'd suggest a language that enable

Above all else, it should be fun. If your son finds programming enjoyable, everything will fall into place. For that reason, I'd suggest a language that enables you to easily make things. I actually think Ruby is perfect, because you can teach him to make websites using Ruby on Rails. I personally have a soft spot for rails because it's how I first got interested in programming. I had no experience in coding and don't have a CS degree, but hacking on rails projects is what initially sparked the fire for me. Two years later I'm working my dream job at Google - that never would have happened if there wasn't a fun, interesting gateway into the programming world.