I don't guess he'd want to make a kitty litter cake? If not, check out the site below. There are 2 pages, A-Z of cakes.

Here is a link that might be useful: Cakes

How about a cake that looks like something it isn't?

Like what if it looked like a bowl of spaghetti? You could pipe the noodles out of icing. Chocolate cake balls for meatballs?

Or I saw a Aprils fools thing that had a slice of chocolate cake as a slice of meatloaf with red sauce (icing) as ketchup and a pile of mashed potatoes that was made out of some cream type thing. Gravy was caramel syrup. Maybe you make a table of food - meatloaf, mashed potatoes, peas?

Also, how about a cake that looks like some futuristic engine? It could be black with all types of tubes and wires coming out of it.

I would also think anything gross would be appealing to kids that age. A face with snot coming out the nose? Eww, I know.

The cake from last year is great!

Maybe a cake, or cakes, arranged to look like burgers on a grill?

Here's a pic of a cake I made. It's SIMPLE, more assembly than baking.

Easy Hamburger Cake
Ingredients
1 package yellow or golden cake mix
1 package brownie mix (any size)
Container of non-dairy whipped topping (thawed)

Strawberries
Kiwi
Sesame seeds
Yellow food coloring
Directions

1. Bake cake according to package directions in 2, 8" or 9" round pans. Sprinkle one pan with sesame seeds during last few minutes of baking.
2. Bake Brownies according to package directions in same size pans.
3. Let cool few minutes then invert onto racks to cool completely.
4. Peel kiwi and slice (for 'pickles')
5. Slice Strawberries (for 'tomatoes')
6. Tint non-dairy topping with yellow food coloring (for mustard)
7. Before serving assemble with yellow cake for bottom bun, brownie for meat, top with fruit, then whipped topping, and the other yellow cake (with the seeds). I assembled my cake about 5 hours before serving and refrigerated it.

Nikki that is a cool looking cake!