Spam filter off for one night...
Last night, I was updating some packages on our server. Among these was SpamAssassin. The update shut down the spam filter daemon, and I did not notice this. Until this morning, when my inbox was full of spam.
Spam filter is off for one night (~12 hours), and I get 71 spams. As opposed to the normal 2 or 3 per day that actually make it to my inbox. Kudos to the SpamAssassin developers for such an excellent product.