The Adventures of Ook and Gluk, Kung-Fu Cavemen From the Future-- The second graphic novel by George Beard and Harold Hutchins the creators of Captain Underpants (along with Dav Pilkey) (Blue Sky Press/Scholastic 2010, middle grade or whatever, 175 pages)
George and Harold have created two cave-boy alter-egos for themselves in this wham bam time-travel cartoon book/graphic novel--the titular Ook and Gluk. The boys are enjoying their life back in .... , running from, and then befriending, a dinosaur, pushing the envelopes of stone-age technology, and tormenting the bullying Big Chief Goppernopper. with their boyish pranks in true George and Harold style.
But when a time-travelling descendant of the chief arrives to pillage the natural resources of the past to fuel his corporate greed in desolate future of 2222. Ook and Gluk, along with the rest of the cave folk, find themselves enslaved. But all is not lost, for Ook and Gluk travel to the future! They bring with them their young, delicately stomached (ie it pukes a lot), very cute dinosaur (who plays an important role in the story)! They train as Kung-fu masters with a Wise Old Sensei! Grow into young cave men! They return to the past and battle robo dinos to save the day! They find (in the case of Ook) young love!
Not the, um, typical, deeply nuanced sort of time travel book I generally review, but heck, the time machine is at the heart of the plot, and it is a temporal paradox that handily resolves everything (in a completely contradictory way, but whatever). It is a lot of fun, and one's boys pounce on it. Even though it's not going to help their spelling, it's a pleasure to watch them enjoying it (and I liked it too).
But when is Dav Pilkey going to write the rest of the Ricky Ricotta books for crying out loud? Me want them for me boys (I studied the handy guide to cave talk at the end of this book).
(Gluk is a cave boy of color, making this book a nice addition to my list of diverse sci fi/fantasy for kids. Adding more diversity are Master Wong and his daughter (edited to add) Lan (when I went back through the book to look for her name, I couldn't find it, so thanks, Anon. commentor, for letting me know she had one after all!)