Oh No! Not Again! (Or How I Built a Time Machine to Save History) (Or at Least My History Grade). It's a mouthful, but it sure can pique a kid's interest.
This story is short, but it's a great jumping-off place for a great discussion about history--and maybe even time travel. Preschoolers may have a tough time with the concepts, but kindergarteners and up will enjoy it. The pictures are big and interesting, and there's a great mixed-up timeline inside the back cover that could be the best place to start your post-storytime chat.
The plot goes like this: a student misses a problem on her history test. She says that the first cave drawings were in Belgium instead of France, so she decides that the best way to fix this problem is to go back in time and ensure that Belgium's cave men beat the French cave men to this great achievement. But this causes some new problems...
Test this story out on your older co-op kids. I bet they'll like it.