I've been procrastinating (wasting time) today. I've been thinking about writing an article about how one should write file system resizers... the obvious method (basically: defrag + update metadata) is fundamentally Wrong, and I've seen many people fall into the Obvious trap (I did myself, the first time around).
Which raises the question in general: should free software hackers write more technical docs / papers (i.e. targetted at hackers)? I think yes... reading over mail archives is often rather difficult, unless you already know a lot about the particular area. And even if you do, it's a lot of effort. Also, I think writing technical docs for hackers will make it easier for the newbie-hackers to see how different hackers think about problems.
So, I've decided it's a good idea, so, now I need to waste some more time to do it ;-)