Let's see, since I've averaged at least a job a year since college, there are a couple of cadidates for the "worst job award".
The first was selling caskets. Now you're probably thinking that it's easy, right? After all, it's something everybody needs. My job was "advanced sales". I had to cold call people and convince them that they needed a casket - now! Needless to say I never sold anything. The other terrible part of this job was working in the basement of the funeral home and encountering grieving families on my way to lunch. I never left work in a good mood.
The second contender is a job that I had as a network administrator. You see, I was hired to work on medical software, but on the day I was hired their network admin walked out. So the boss decides that since I have *some* computer know-how, I can EASILY perform in this capacity. I explained to him repeatedly that this was well beyond my capabilities. Did I mention that this job was in 2001, and the newest machine in the office was from 1994? There was also $0 budget for purcashing new equipment. The owner didn't understand why I couldn't make the machines run the latest software. I lasted for about a month at this job.
I think we need a spin-off of this thread for worst job interviews, because I have a whole slew of those!!