My last birthday cake was pretty cool – it spells my name in morse code using maltesers and chocolate fingers.
When I was six my cake was a chocolate cake with the middle bit cut out and white icing in the shape of a dinosaur skeleton, then with the cake crumbs put back on top of it. We dug up the bones with spoons! We can’t find the photo of that one, though.
I found this site that shows you how to make a cake that looks like Jupiter – even when you cut into it!