File this under "odd and possibly disgusting but fascinating anyway:" Chocolate Avocado Cake at Not Quite Nigella. Check out that photo, it is something special.
(It *is* egg-free, dairy-free, and nut free, and probably quite rich. I'm tempted, although I think I might rather have it in the form of a cupcake. How do people think avocados would do as an egg replacer in general?)