Often that “dead” pen isn’t dead at all, just a little clogged up — usually with dry ink. ClueDB user Wordie shares an easy solution: By holding the tip of it to a lighter for just a few seconds, you can melt the ink on the ball and bring the pen back to life. Alternatively, if you don’t have a lighter around, some hot or boiling water should do the trick too. This seems to be a fairly well-documented tip, so it should be good for getting you out of a bind.
Unclog stuck ballpoint pens [ClueDB]