Stock Market Game
Start with a brief discussion or explanation of what stock is (pieces of ownership in certain companies) and how stock markets operate (supply and demand largely determine the value of stocks, as expressed by their price).
Tell students that you are going to simulate how the stock market works. Each one will need a piece of paper, which they should turn "landscape" style (lying on its side). On your classroom chalkboard, write 5 publicly traded companies that would have been around in 1929 (I like to use RCA, Coca-Cola, Chase Bank, Rawlings, and Sears) on the left margin of the board, leaving space in between.
Across the top of the board, list 5 months - June, July, August, September, and October. Under June, make up prices for each company. "Give" each student $1,000 of imaginary funds, and have them invest in the available companies. Tell them that they may not keep any money as cash, and make sure that they are keeping track of how many shares they have purchased, not just how much money they have spent. Track the performance of their purchases over the next three months, making up prices as you go. Make sure that prices rise, steeply in some cases. Build class excitement by having kids compare how much they have made. Try to create a sense of competition. In October, "crash" the market to levels considerably lower than the prices you started out with in June.
Once the market has crashed, debrief the activity. Talk about how much unhappier people would be if the money were real. Then explain the concept of "buying on the margin" - buying stock with borrowed money. Buyers only needed 10% of the actual value of the purchase in cash; the rest could be borrowed from a bank or other lending institution. If the value of the purchase fell below its original price, it would trigger a margin call in which the lender would ask for their money back immediately. This would force the purchaser to sell and also somehow raise the balance owed in some other way. All of these sales would drive prices stock down, triggering more margin calls.