My son's daycare just finished up a great project. They ordered Painted Lady Caterpillars and observed their metamorphasis.
But what made it special was that the kid's "journaled" the whole process.

Each time they would draw a picture of what they say (bunch of scribbles in Ry's case) and then tell the teacher what they saw. She would write it down word for word, even if it didn't make much sense. It's hysterical to see your kid's little speech mannerisms in print that way. "they goed in they cocoons" and "uh...they caterpillar turned into a butterfly. I said a cocoon. For more cocoons." were my favorite entries.

I may have to find some things for him to journal about at home and do the same thing. When I am old and senile, it'll be fun to have those reminders of how he used to talk.