A good joke activates about every part of your brain, according to Holistic Online: the cortex's analytical left hemisphere, the frontal lobe and center of emotionality, the right hemisphere's synthesis capabilities, the left's pattern finding processing, and the sensory processing occipital lobe. "The increased fluctuations in delta waves reached a crescendo of activity and crested as the brain 'got' the joke and the external expression of laughter began." (Yawn--let's not think that hard about it.)
Searching for kids' jokes online is like exploring a mine-field. Many comedians seem to think that shocking an audience is the same as entertaining them. But here's an excerpt from "500 Hilarious Jokes for Kids" by Jeff Rovin:
Q: What's the name of the nosy superhero?And another from "The Everything Kid's Joke Book" by Michael Dahl:
Q: What do you get when you cross a ghost with a firecracker?