Previously I announced a plan to have students in my PSTAT 262 class model and forecast actual time series. Here is another example of a possible dataset for modeling which concerns US Debt from (almost) all sources as a percentage of GDP. As mentioned here, this debt does not include a few trillion in “off balance sheet” financing, contingent unfunded pension plans for corporate and state and local governments, or unfunded liabilities of the U.S. government for such items as Medicare, Social Security and other programs.