Magic.

No, really. I'd expect most potential explanations to fall into one of three categories:

1. "Wait, that doesn't actually explain anything!" (throwing around a code word like "midichlorians")
2. "Wait, that's totally unbelievable!" (like, military artificial intelligence experiment gone mad, somehow escaping into a toy factory)
3. "Wait, that's just plain stupid!" (they are ghosts trapped in plastic bodies, somehow ending up with Microsoft voices)

So I'd rather take no explanation over a disappointing one.

Isn't a highlight a little spurious?

Good point. Still wouldn't mind getting some form of lampshade hanging. 

Oh, I don't know, isn't giving yourself a "kudos" pretty spurious in itself?