The Phantom Tollbooth. We didn't get do it this summer after I saw how much fun we could have with it during the school year. 

"We're having a special treat today," said the king as the delicious smells of homemade pastry filled the banquet hall. "By royal command the pastry chefs have worked all night in the half bakery to make sure that -"
The half bakery?" questioned Milo.
Of course, the half bakery," snapped the king. "Where do you think half-baked ideas come from? Now, please don't interrupt. By royal command the pastry chefs have worked all night to - "
"What's a half-baked idea? asked Milo again.
"Will you be quiet?" growled Azaz angrily; but, before he could begin again, three large serving carts were wheeled into the hall and everyone jumped up to help himself.
"They're very tasty," explained the Humbug, "but they don't always agree with you. Here's one that's very good." He handed it to Milo and, through the icing and nuts, Milo saw that it said, "THE EARTH IS FLAT."
"People swallowed that one for years," commented the Spelling Bee, "but it's not very popular these days - d-a-y-s." He picked up a long one that stated "THE MOON IS MADE OF GREEN CHEESE" and hungrily bit off the part that said "CHEESE." "Now there's a half-baked idea," he said, smiling.
Milo looked at the great assortment of cakes, which were being eaten almost as quickly as anyone could read them. The count was munching contentedly on "IT NEVER RAINS BUT IT POURS" and the king was busy slicing one that stated "NIGHT AIR IS BAD AIR."
"I wouldn't eat too many of those if I were you," advised Tock. "TheY may look good, but you can get terribly sick of them.
"Don't worry," Milo replied; "I'll just wrap one up for later," and he folded his napkin around "EVERYTHING HAPPENS FOR THE BEST."