In the episode “Toody and the Art World”, he plays Karpathia, a modern painter. As it happens, Toody likes one particular picture, and Karpathia declares him the only person who understands his work.
Darden plays Karpathia with some similarity to Prof. Walther von der Vogellweide, and we can get a bit of an idea of what Darden’s “lectures” were like.
That series was pretty poor, and this episode is no exception. But it’s on YouTube (in 2 parts), and a fan has bookmarked Darden’s scenes so you don’t have to wade through the whole episode.
Darden’s scene in part 1: http://www.youtube.com/watch?v=zbhkDHzCAlU#t=3m14s
See the part 2 comments for the bookmarks.