Spotted this in the
So anyway, after some prodding in the comments, more became clear. The Parkville in question is, as I suspected, the one adjacent to Baltimore, Maryland (Harford Road was a strong hint). The set, which will be performed outdoors, is 45 minutes to an hour long and is free. Finally, there's a website for Collectors Corner which has plenty of information which is totally unrelated to "Bene Gesserit Witch". (The Bene Gesserit are the original "Spice" girls, for those of you who don't know.) Is it possible I'll be there, if only out of curiosity? Yes. Is it probable? Can't say.
EDIT: With a little additional searching, I discovered the benegesseritwitch myspace page, which you'd think would have been a relevant link to include in the original post. (There are MP3s there.)
EDIT: My brother came up with "The Sleeper Must Awaken, And Thus Bring Home The Bacon" for a Dune song title.