I don't know if you've already seen this, as it was featured here a couple of weeks ago, but if you have any interest in mathematics / programming (I'm going to

I don't know if you've already seen this, as it was featured here a couple of weeks ago, but if you have any interest in mathematics / programming (I'm going to assume you do) and want to learn about all sorts of interesting maths that will probably show up while programming, http://courses.csail.mit.edu/6.042/fall10/mcs-ftl.pdf http://courses.csail.mit.edu/6.042/fall10/mcs-ftl.pdf is an excellent pdf written by two MIT professors and a Googler. I know instapaper doesn't support pdf's right now but you could always run it through google docs and save the text from there.