Well i think that there should be new forum themes i typed in one search on google and found this on the first site
http://www.themesdb.com/forum_themes.page_1.html
Well first of all those themes are for phpBB and in no way compatible with SMF. And there are a few new themes that Jeremy recently added, "Extreme6" and a Halloween theme. To get them go to Profile>Look and Layout>Current Theme.
i know how to do that, i have a topic on it explaining how to do it, and am currently using the halloween theme myself, i was suggesting that they have more than that though