Lean Production / JIT - one piece flow
This is a simple game to illustrate the advantages of one-piece-flow vs. batch production. Total time required: about 15 minutes.

I use it as part of an introductory lecture to Lean Production/JIT for undergraduate students.
Supplies needed: 14 index cards (or large stickies), 8 writing instruments, 2 stopwatches

You need a total of 12 student volunteers -- two "production" teams of 4 each, two inspectors, and two timers.

Seat the 4 members of each production team next to each other. Seat the two inspectors next to each other. The timers need to be able to see the last person in each team as well as the inspectors.

Each production team is going to produce seven (7) index cards with some identical phrase written on them by each of the 4 team members. I usually use the phrase "Mucha Muda" (translation -- lots of waste) but any phrase will work. Be specific in how the phrase must be written (e.g., printed vs. cursive, upper vs. lower case, etc.).

Team 1 is the one-piece-flow team. As each person completes the specified phrase on one index card, they pass it to the next team member. The final team member passes the completed card (with four identical phrases written on it) one-at-a-time to the inspectors.

Team 2 is the batch production team. The 1st team member must complete all seven (7) index cards before passing them on to the next team member. When the final team member completes all seven (7) index cards, he/she passes the completed cards (with four identical phrases written on each of them) to the inspectors.

The two inspectors jointly review each card and note any discrepancies (misspellings, upper vs. lower case, missing phrases, etc.).

The timers use a stopwatch to time each team. For both teams, the exercise starts at the same time when the Instructor gives the "Go" command, and the time stops when the last card is handed to the inspector.

For the rest of the class beyond the 12 volunteers, their job is to observe the exercise and note any advantages or disadvantages they see in each team.
Expected result: team 1 is significantly faster (usually about half the time of team 2) and has fewer quality errors.

Conduct a class discussion regarding what's behind the results. What are the pro's and con's of one-piece-flow vs. batch production? If one-piece-flow is so great, why does anyone use batch production? Issues like setup time, container sizes, etc. drive batch production. Explain that as you discuss lean production/JIT, the goal is to achieve one-piece-flow so issues like setup time, container sizes, etc. are important to address. Also discuss how the production team members felt. Generally, team 2 members alternate between sheer boredom when they're not working and high stress when they are working, whereas team 1 members had a steady comfortable pace.