I made rods out of our Unifix blocks to represent the start of the Fibonacci sequence, traced them onto paper and asked the girls to match them up (which was easy for them). Then we went through each one and counted the blocks (as I wrote the number underneath):
I told her that this pattern is all over nature, and then showed her this snail's shell drawing to match up her rods to:
Then I showed her some photos of flowers online and we counted the petals (3,5,8,13, etc..). She even drew her own petals:
The final activity, which E participated in as well, was coloring and counting leaves and flowers based on a real plant (called the "sneezewort", which the girls found hilarious):
When we were done, and the girls were still playing with their blocks (I don't know where they find the energy!), L announced that she had "so much fun this afternoon with all these activities". I think that the topic of Fibonacci numbers was really more for Mommy than the kids, but I'm really glad my girls had a good time. Even if the only thing my kids got out of this is that playing with numbers is fun and gets Mommy pretty excited, and if they enjoyed the quality time we spent together, then I'd still be a happy parent.
UPDATE: I was so inspired by how much my kids enjoyed early math "games" that I created the La La Logic Critical Thinking Curriculum for 3-6 year olds, which includes online brain challenge games, printable worksheets, enrichment activities and more!