I have an Annabel Karmel cookbook which has quite a few fun ideas for making food look like fun things
Cannelloni (easy to do vege - spinach and cheese or pumpkin) that looks like people under a blanket. Use button mushrooms for heads, egg noodles for hair and olives for shoes.
Pizzas with the toppings arranged like a face or animal face (AK does rabbits)
Sandwiches cut out using cookie cutters
Fruit arranged to look like fun things on the plate
Checkerboard sandwiches (make with one slice white, one slice brown and then cut in four and alternate squares on the plate).
There's more, will have a look when I have a mo and post later