Hopefully you've all heard about theblaster worm that's been infecting computers. (if you haven't, go here to get the patch so your computer doesn't get infected). It only affects Windows 2000, NT 4.0, server 2003, and XP.
Anyway, there is apparently a new worm going around that exploits the same security hole. Thing is, instead of attacking your computer, it fixes the problem. Good to see a hacker trying to do some good. At the same time, it's not that good because it will reboot your computer while fixing it (whether you are busy working on an important unsaved document of not), and it is slowing down networks as it searches for vulnerable computers. Well-ntentioned, not so good in practice. Anyway, get the patch if you haven't already.