Ask HN: What do you do while your project builds?

I'm currently working on a program that takes around 30 seconds to build, when making changes to a single file. So far I have been switching to Chrome and checking HN/News/Facebook whilst it builds. Inevitably I don't switch back immediately when it finishes building, and the distraction to something completely different no doubt decreases productivity. I suppose I should just stare at the build screen and think about what I'm going to do when the build finishes. What does HN do in these situations? What if the build time is into the minutes?

inb4 relevant xkcd 303.