Xanth is the Punniest Book Series Evar!
Piers Anthony has done an amazing job creating an amusing fantasy world full of the most groan-worthy puns.
The series is called Xanth and I highly recommend you check it out. The reading level is about appropriate for a person in later elementary school. However, the stories would also be awesome for reading to a younger audience.
Here is a great excerpt from one of the books I’m reading through:
They set off down the riverbed, bound by bound, using their little wings to steer the bounds and keep them within bounds. It was the gargoyle way.
Before long the dry riverbanks changed color, turning yellew. Gary paused, "What’s the matter with the ground?"
Mentia looked, "Nothing. It’s just doing its thing."
"But it’s all sickly yellow!"
"No it isn’t." She raked a claw across the dirt. Golden coins rolled down into the channel. "This bank is pay dirt. And there’s a mint." She pointed to a plant with odd oblong greenbacked leaves and round golden flowers with serrated edges. "This is the bank where the money comes from, is all."
"Money? What good is it?"
"No good that I know of. But I understand they love it un Mundania."
"They say that the love of money is the root of all evil."
She looked at the mint’s roots, which did look bad, if not actually evil.
"But doesn’t that mean that they think it’s bad?"
"No, Mundania is such an awful place that tehy must love evil."
Gary nodded, "That does make sense."
"Pennies and cents," she agreed.
… I love it!