If you're willing to accept innovations in place of inventions and if you're willing to consider the central message of OP's post i.e. needing a childlike sense of wonder, then...

1. "Mum, when I grow up I am going to invent a telephone with no wires that's also a flashlight, a compass, a map, a jukebox, a movie theater, and even an ENTIRE computer!"

2. "Dad, when I grow up I am going to invent a table saw that will JUST KNOW when it touches your finger and it will disappear so fast that you'll only get a little cut next time!"

3. "Sis, when I grow up I am going to figure out some way to make it possible for even six year olds like you to have their own TV channel and put whatever you want on it! You can show everyone your toys and dresses. We can call it Roxanne-TV!"