Photo Scavenger Hunt - Take photos around your yard, print them out, trim, place 2 back to back in self laminating pouches, punch a hole add a binder ring. Let them tell you about it after- which ones were hard to find.
Letter Practice: Glow in the Dark Letter Hunt. These were done with glow in the dark letter beads. I wonder if painting letters on rocks with glow in the dark paint, and then leaving them in the sun would also work.