Cosmic, by Frank Cottrell-Boyce, is a fun and funny mid-grade read, with a heart as big as the solar system. The main character Liam is very tall for his age, so he is routinely mistaken for an adult. (Apparently the main differences between boys and their dads are height and the availability of facial hair.) When Liam gets a chance to attend the opening of a brand new amusement park, he brings along his friend, Florida, to pose as his daughter. But the theme park is in China, and the amazing new ride is actually a trip into space aboard a rocket. How Liam, and the other kids, and their dads react to the challenges thrown at them by the cagey theme park owner propels Cosmic's plot to the moon and back.
Liam's voice, both youthful and wise, delivers his many ruminations on the state of being a kid vs. that of being a dad, as well as on being a "regular" kid vs. a super achiever. It's fun and weird, and very sweet. Frank Cottrell-Boyce has written two other quirky, laugh-out-loud winners, Millions, and Framed, which are both mid-grade like Cosmic.
Recommend these books to people who aren't looking for dystopian or supernatural terrors, just some good, kid-friendly fun. I would say they were in the same company as the wonderful Casson family books, by Hilary McKay (which began with Saffy's Angel) and the equally lovely Penderwicks books, by Jeanne Birdsall.