Last week, the Linux in Boise Club allowed me to present a short talk. Since they found me through my Perl work, I gave a small advocacy talk entitled Why I Like Perl. It went really well, though having several books and miscellaneous pieces of swag to give away always helps.
You might notice that there's not a lot of traditional "advocacy" in the style that turns people off. I was more interested in talking about the advantages of Perl that I enjoy than discussing the bits of other languages I don't enjoy. In retrospect, that worked pretty well -- there were several interesting questions about Parrot, Ruby, and Java.