This is the second book by this author/illustrator that I’ve read (the other being Dancing with Grandma), and I’ve loved them both.  The illustrations are utterly charming, and the stories are whimsical and fanciful, even while they are very relatable (and I like that the grandparents are spunky).  This one tells of a young boy spending the day with his grandfather, and all the adventures they get up to (at least in their imaginations) with the things they find laying around Grandpa’s    shed and yard, from tree house and tire swinging to building a race car, rocket, and sailboat, and battling dragons in the bargain.