When you have 30 minutes to burn, the short film Patent Absurdity is worth a look. It gets a bit heavy-handed sometimes, and as can be expected, it might be a little one-sided, but it does an acceptable job of picking over American patent structure and its history.
Of course I say that not knowing word one about either, except for what I see and read by way of using Linux. So my opinion is formed over a very superficial — and probably likewise one-sided — frame of reference. Be that as it may, it’s still worth a half an hour of your life.