Wheeeee!!!! --hey, at least it's a fun joke for kids!
Atrophy.
Because she's always drinking from the coup de Grace. (This was my sister's favourite joke when we were kids. Once our mum flipped out on a long car journey because she told it too many times).
Wheeeeeeeeeeeeeeeeeee!!! I'll see myself out.
Because of sanitation reasons.
Boomsticks
A Holly Davidson!
Hare loss.
Anyone else got some fun jokes your kids have told you?