Fortunately, the Milk by Neil Gaiman

A father goes out for a milk and when he returns he has a very odd, involved story to tell.

I picked this up for my son and I to read together. But so far I haven't gotten around to reading it to him. I did read it myself. It's not a very long book and I basically read it while I was sitting with him as he did his homework. It is an utterly charming book. The dad is sent out for milk so his kids can eat their cereal and so he can have milk for his tea. But he is gone for a very long time and the kids begin to wonder where he is. Then he comes back with the milk and a long story involving space aliens, time travel, talking dinosaurs, and a whole host of other adventures. It's pretty great. For me, it's basically what Douglas Adams might have written had he written a children's book with its certain cheeky irreverence. It's a super fun book with wonderful illustrations by Skottie Young. I think my son will enjoy it when I read it to him.