After returning to Atlanta Thursday night, I got up Friday and went to the regular exercise class and the "extra" one, then came home and started on a birthday cake for my nephew, who just turned 5. Said nephew has forsaken Spiderman for Harry Potter of late (the first book has been read to him, and then he was allowed to see the first movie), and so he needed a Harry Potter birthday party. My sister-in-law conceived the idea of buying some miniatures to go on top of the cake, and suggested that I just try and make the cake look like a stone wall, a la Hogwarts Castle. Then the figures could be placed on top, and we're done.
All was accomplished, though it took the rest of Friday and the help of my nieces on the decorating. Baked the cake (from a mix), covered it with a thin crumb coat (it being chocolate cake, so stray crumbs are very visible), then mixed up 3 shades of gray for the stones. The top of the cake got a thicker layer of white frosting, which was later sprayed with black food coloring spray to get a gray. We applied small blobs of various grays to the sides of the cake and patted them flat with fingers dipped in cornstarch--each niece and I had a different gray, and we went back and forth filling in the area to get a mixed set of stones in our stone wall. I then added a few sprigs of grass between some of the stones (green frosting), and used the rest of the gray to make boulders around the base of the cake.
Pre-made "Happy Birthday" letters (in Griffindor colors) were stuck on the front, Lego and other figures applied to the top, and five-plus-one-to-grow-on candles added in a corner. Voila! Birthday cake. Not anyone's idea of polished perfection, but the birthday boy was happy.
Detail of "stonework":