I'm a geek, the geekiest podcast I listen to is not the SGU, it's Security Now! with Steven Gibson and Leo Laporte. Steve recently said he was going to do an experiment on Vitamin D production on himself. He also said he had read 50-60 journal articles on it, although he makes it clear he's not a medical professional. I thought the SGU might be interested when the subject was brought up in science of fiction. Anyway, he'll be talking about this on the next Security Now! podcast (ep. 209) it's hosted at grc.com
Steve isn't involved in skepticism as far as I know, and while his job involves mathematics, logic, and science, Computer Science is definitely a softer science than the kinds I hear on the show, although I'm a relative n00b listener. Leo Laporte said Gibson is the most scientifically minded and the least superstitious person he knows, I don't have any experience of this, but I respect Leo Laporte's word.