DLTK's Crafts for Kids
Dog Bone Birthday Cake

You can use this cake for dog themed birthday parties (Clifford the Big Red Dog, Blue's Clues, Scooby Doo, etc.) or you can feed it to the human guests at your pet's party.

This makes a nice BIG cake

Materials:

something to set the cake on -- we made our own cake board by duct taping sheets of thick cardboard together (we used box lids for this) -- this was daddy's part of the process. We then covered with Aluminum foil (you could also cover with a waxy or shiny gift wrap.
9 x 13 or 8 x 11 (any rectangular shaped) baking pan. If you don't want such a huge cake, you can actually use a square pan... You'll just have a shorter bone.
4 round cake pans (or use 2 round cake pans and do your baking twice)
3 cake mixes (whatever flavour/recipe you prefer). You don't have to have all the same flavour if you don't want too. You can make a white rectangle cake and chocolate round cakes.
4 containers of chocolate icing (or you can make colored bones -- a blue one for Blue's Clues or a red one for Clifford with white icing and food color paste) You'll likely have icing left over, but I like to make sure I have enough.
Optional: Fruit by the Foot (fruit roll up)

Bake your cake according to package directions Kimberly adds the following tip: "P.S. I found it easier to remove the cake in one piece from the pan when I buttered the bottom of the pan and sprinkled on flour before putting the batter in."
If your cake has a bulging center, trim it a bit so it's flat on top (this shouldn't be a huge problem in the 9x13 rectangular pans... I didn't have to trim mine, but you will likely have to trim the round cakes.). Turn the cake out onto a piece of Aluminum foil. Make sure you run a knife around the edges first so there's nothing sticking.
Cut about 1/6 of the tops of each of the 4 round cakes off (red dotted line) Square off the left side of two of the cakes and the right side of two of the cakes (blue dotted line). You should only be cutting a smidge of cake off here. (if you're confused, look at the diagrams to the right and cut along the red and blue dotted lines). If you're nervous about all of this cake cutting, trace your cake pans onto white paper and do some practice cutting and assembly with paper. To be honest, I do this EVERY time, just so I have a practice run before cutting the actual cakes grin.
Center the rectangle cake on your home made cake board. line your left and right edge (blue line) cuts from the round cakes with the ends of the rectangular cake. The red lines from the round cakes should be touching. I've left the lines on the diagram to the right to help you keep track.
Ice the cake with chocolate icing (or white icing colored the way you want it). You can use the icing to fill in any gaps there may be between the cakes if you didn't get your lines perfectly straight.