Probability Games with Monte Carlo Simulations

I've made something. And, I think it is pretty cool.

My colleague is doing some probability investigations with her 4th grade students. She's got a number of games from Marilyn Burns' probability book, and she is having students students investigate the experimental probability of the games.

One of those games is called Shake and Spill. Grab six 2-sided chips (or coins) and flip/spill/spin them so that they land on a random side. Record the result and repeat. My colleague is having her students pool their results to better estimate the relative probabilities. Cool!

But, I wondered if they would generate enough data (and generate it fast enough) to see the Law of Large Numbers in action. So, I built a website that would simulate this game over and over and over again with a live graph. You can check out the website here.

I'm planning on building more of these. They are an awesome way for me to practice my Javascript and I think that they may be helpful to others. What other probability simulations would you want?