Inspired by some library books about "playing with your food", we decided to do the same thing. I cut up some pita bread into triangles, made some hummous, and laid out various veggies along with the kitchen shears.
I sometimes make my own pita bread using this recipe: http://mideastfood.about.com/od/breadsrice/r/pitabreadrecipe.htm
and hummous by getting out my blender and tossing in a can of chick peas, a little water, olive oil, 2T sesame tahini, lemon juice, garlic, and cayene pepper to taste.
Some ideas are sprouts for hair (my kids actually ate them this way!), olives or capers for eyes, carrot pieces for eyes, cucumber pieces for mouths, etc. You could also cut the florettes from brocolli for hair. The other nice thing about this is if you buy store bought bread or bake it the night before, there's no cooking involved so it's a great summer lunch or light dinner. Have fun!