I made the buildings with an old cereal box. Then we took some ornament hangers off our christmas tree...yes our tree is still up... we shaped the hangers to hang Flin off the side of a building, since Finn driving up the side of the building in CARS 2, is my sons favorite part. I even put a car crash, since it's a boys cake.
I gave him a big piece of cake, thinking I was spoiling him! But he only ate two bites and left the rest for me. It was a fun FUN birthday!