I've always wanted to, but I haven't attempted it yet. I would like to go as Illyria (she's on my avatar), but only if I could get it to look identical (or nearly). I'm not sure if I could customize a black wig to get the blue highlights, or if I'd do the makeup properly, plus she's (the actress) a lot taller than I am so it may look silly. But I've bookmarked some detailed instructions from people who have cosplayed it.