One of my early memories is of entering a cake decorating contest. I was probably nine years old and we were living in Richmond B.C. I have no actual recollection of how I decorated my entry: I just remember how betrayed I felt when I realized that many of the elaborate entries were probably not decorated by the children who entered them.
Five years later, my little sister was born and I became her personal cake decorator. My method was to paint a picture with icing, so that she had a unicorn or a Holly Hobbie doll or whatever she wanted that year on her cake. There was no contest; just a celebration when my work was briefly displayed, and then consumed.
When my own kids were little, I decorated lots of cakes, but I remember almost none of them. This may be a function of being so sleep deprived that the memories didn't stick, or it may be that the parties I threw for them were so elaborate that the cake was just one element among many. For instance, I don't remember the cake that went with the Star Wars party. I do remember the dowelling light sabres that destroyed the Death Star pinata.
One of the last cakes I remember decorating was very simple. My younger son had won a rock climbing party, and so I made a rock climbing cake. I cut a chocolate cake into randomly sized chunks, piled them into a mountain covered by icing, and arranged little lego men as climbers. It was awesome, and it was easy enough for any 9 year old to replicate.
There is something wonderfully extravagant about pouring creativity and hope and celebration into something that will be admired for a few moments and then cut into pieces and forgotten.