For lots of varied reasons many of us spend substantial class time on inventory. The 
Heizer / Render text covers inventory in Chapter 12 (managing inventory and inventory models), Chapter 14 (lot sizing), and Chapter 11 (measuring assets committed to inventory and inventory turnover).
One way to engage students in discussions of inventory, and perhaps understand its significance better, is to have them use real turnover data for companies or industries they know. We show how to do this in Chapter 11, Examples 5 and 6, where we use Home Depot and Pepsi data. Assignments where students compute and compare these ratios can be facilitated by the use of annual reports as most annual reports provide enough data for the calculations. Alternatively, data on an aggregate basis are available and down loadable from the U.S. Census Bureau.
Additionally, Quarterman Lee has just published some Wholesale Inventory Turn Data that you and your students might find interesting for developing industry comparisons. His raw data are from the U.S. Census Bureau, but he has organized it into 18 broad categories and more than 260 subcategories. He has a modest fee of $6 or $8 to access the down loadable data.