I am a huge fan of most childish games. Despite being just about to turn 30 I am obsessed with Pokemon (OK obsession is a slightly strong word but I do love it). Mostly playing it though I do find the cartoon somewhat entertaining as well.
I am the same for most games like that - which others consider 'childish'. For example I was somewhat gutted that 'Chaotic' never really took off as I thought that was a game with a considerable amount of potential
I also prefer more adult gaming - I love my X-Box 360, especially the Assassins Creed games, and also own a Wii which I play fairly regularly.