Folgers instant coffee on paper, "Good Boy".  This was for the art league show that had a theme something like "mocha, cappuccino," and something.  I did not know what to do with that so I decided it would be fun to paint with coffee, taking the theme literally.  I found it takes a really thick soupy mixture, several applications, to get the dark parts, and a very careful thinly applied mixture for the light parts.