I did this over the summer with my classes, it's very fun indeed! We first did a scavenger hunt for items to print, and then took turns using a few sheets of plexiglas to expose them in the park. We also made book markers too by first trimming the paper into strips then exposing/wash/dry and mounted then on strips of mat board.

I recommend to buy the sun print kits and self coating is messy and can stain.