One joke that both my kids loved at that age goes as follows:
There's this farmer who sits with his dog on a horse-drawn cart. Suddenly, the horse turns its head and says "Beautiful weather, boss!". Obviously, the farmer is stunned. Then the dog nudges him and says: "Huh that's funny. That horse just talked.".
Yes! I totally forgot about Imajica. I need to re-read it.