I guess its not doing any work that people don't want to do, but more work that makes you an asset to have. At my old place of employment, I was making $9.75/hr. When word got around that one of the supervisors was leaving, I started putting in extra work and making sure the supervisors/management noticed it. I also told them I was interested in a supervisor position when one became available. So, when the guy left, I was the next best person to take the job since I was the only one who had shown initiative.

A few months later, I caught wind that our assistant manager was going to be leaving. So, I spent my free time hanging out with him and getting to know how to do his job. He was happy to have someone help him with the schedules and paperwork, so he taught me everything he knew. Once he put in his resignation, he pushed for me to take over since I already knew how to do most of his job.

Fast forward to a year later, and the site manager revealed to me he would be moving up to a corporate position soon. I did the same thing as before, and within a couple of months, the manager was telling our RM that he wanted me to take his place once he left. I ended up rejecting the job and moving into a different field of work, but still.

<2 years and I went from part time hourly to $36k/yr w/ benefits with an offer for $50k/yr.

Obviously YMMV, but getting on your employer's good side and taking interest in your superior's activities can have its advantages.