One unit we in in my preschool class at the end of the year was a water unit. We spent some time focusing on the ocean since we live so close to the water. While I was out for a meeting I had the students work with the substitute to make jelly fish. I just love the way they came out. Unfortunately I don't have pictures of the process, but I do have a picture of the final product. To make them we simply cut a paper plate in half and colored half. Next the students counted out 10 tentacles from crepe paper. The students then glued the tentacles on. I retrospect I probably would have had the kids cut the plates themselves and use a stapler to add the tentacles. That way we could add some extra fine motor practice in.
Another activity we did that the kids really enjoyed was pretend to be turtles. We did this by crawling around on all fours while having a "shell" balanced on our backs. Our check was a carpet sample that I use to make places to sit in the class room.