Here are just a couple I have. If anyone else has some I'd love to hear them. We're not taking video games....
Photo Scavenger Hunt - I will of course be with the kids but it gets my oldest thinking.
Identification - we'll be taking our field guides:)
Identifying constellations - I've actually never done this before. I'm very excited!
Drawing messages in the sand and taking pix.
Rock and shell collecting.
We'll also be doing all the "normal" stuff like playing at the beach, etc...