SOE's free to play MMO Free Realms has seen quite some success since it launched last year, with SOE reporting 8 million registered users (which is not to say 8 million paying customers or even players, mind you). The game continues to be updated, and now SOE have added rideable dinosaurs and dragons to their kid friendly MMO.
Take a look at the pictures below and see if they manage to tickle your inner child. Our souls are already dead, so I'm not so sure they will have any greater impact on us.