Rocks Glued to Paper

This kind of activity gives my little pirate motivation to take his well-needed nap! :)

He comments on something he sees in a book I read to him (i.e. rocks glued to paper and labeled in a Magic School Bus book).
     I say, "Yeah! That's neat! How about you take a nap, then we can find some rocks and glue them on paper when you wake up!"
     He responds, "Okay! I need my blankie." Then, heads up the stairs to his room. Lays down, requests a song, then sleeps.
     When he wakes up...we find rocks outside (even in the rain or snow), and glue them to paper (even if it only was a 2 minute activity).
     He's slept!