Hongkiat.com has a great post about 11 different sites that you can visit to create cartoon characters of yourself. My favorites were the South Park Studio and Simpsonize ME (obviously to create your own Simpsons character.

I created a cartoon likeness of a family member and had it made into a photo cake. Regular photos look too cheesy but give your friend/loved one a cake with an cartoon likeness of them and they will love it.