Browsing through the MIT OpenCourseWare, I came across the details of a variability simulation otherwise known as the Dice Game. There is a ton of great stuff on the MIT site and I could spend a few days sifting through the info. This game teaches "the impact that variability has on process performance." As a trained six sigma blackbelt, I am interested in how they use the dice to simulate a process. They also throw in a lean discussion of takt time, cycle time and WIP, so this is an all-encompassing package, perfect for a lean-six sigma group.
Here's the flow:
As you can see, the "process" is to pass plastic chips from one station to the next. Every day, or game turn, each operator rolls a die to determine how many chips to pass. They are passed simultaneously to prevent passing of the same chip down the line in one day. As can be predicted, the flow isn't exactly even from station to station. There's some fascinating graphs showing a computer simulation of over 200 game turns, and what happens when you reduce the variation using only 3's and 4's from the die rolls, or reducing the variability of the demand.
There seems to be more than enough information here to carry out this experiment with your group. The main page for the courseware is located here. You can find the Dice Game in the Day 3, subsection 3.2, where you can also find instructions for the computer simulation which is an Excel spreadsheet, also included.
Note: Edited this post May 3, 2014 to fix broken links.