Back in December, I did my first turn as an "expert" on something, on the technology of Middle Earth for the Discovery Channel. You can see the website for it and the videos here. (I'm day three)
Also, in case you're a graduate student in a medieval subject, in the mood for applying to give a paper, Vagantes' second occurrence is coming up next spring, with an application deadline of October 1st for papers. Yes, a long ways off, but you're forewarned. Vagantes is co-sponsored by the University of Toronto, Harvard University, and Cornell University. It's a fun gathering and, even if you don't want to give a paper (or unfortunately are turned down), it's still worth attending. Based on last year, there should be a fair chunk of the audience not giving papers.