We use an antiquated windows timekeeping app at $WORK that's been quite tempermental recently. It worked fine for months, then someone messed with my network config, and it's been throwing GPFs when launched for about two months now.
So I call the help desk, and yadda yadda yadda, it was working on Monday. Then it crashed on launch on Tuesday and Wednesday. Today, it's working. Go figure.
As far as I can tell, this program is exhibiting a truly odd bug - it crashes on days of the week that have an odd number of letters in them.
Pretty crafty, that.