Some weeks ago, I discovered I was included in the list of people who were going to do talks in this year's Campus Party, although nobody had asked me in advance. A few weeks later I did get a mail regarding this, which I answered, but I never heard anything else, so I assumed I didn't have to do it in the end.
Well, it actually seems like they still counted on me, apparently, as I was listed in the time table to do a workshop on Debian last Tuesday. So not only they didn't call me to give me details on dates for the talk, but they also didn't remove them from their planning. I imagine participants went into the room last Tuesday, waited a bit for me, thought I was a bastard for not showing up and went back to their computers to play some more of whatever the current 3D bloodfest game is right now.
In the case that anyone at Campus Party is reading this: sorry, I didn't show up because I was never informed.