The newest episode of Radiolab is about parasites. It features what is one of my favorite links from the past few years: the story of Jasper Lawrence's quest to infect himself with hookworm in order to cure his asthma (also available here).
Based upon what I read, and what I learned about the hookworms I decided that I was going to try and infest myself with hookworms in an attempt to cure my asthma. I was not willing to wait ten or more years for the drug companies to bring a drug to market. It was obvious to me that hookworms, for a healthy adult with a good diet, are quite benign. This account details my experiences, how I went about it, and the things I have done since infestation to calibrate my level of infestation so that in the end I was able to cure my asthma and hay fever with hookworms. These same techniques are of course applicable to any hookworm infestation, whether you want to control asthma, hay fever, colitis, Crohn's disease or IBD.
Lawrence even sells hookworms to others so that they won't have to travel to a third world country to contract them.