A downloadable Excel spreadsheet, created by Peter Ponzo. You type in a function (or select one of the existing function) and the spreadsheet will generate four graphs, one of which is the second derivative of the function. Students have to choose the correct graph from those given. You can also download a version that prints two problems per page. Very clever, and three thumbs up!

Link
http://www.gummy-stuff.org/curvature-questions.htm

Excel Spreadsheet
http://www.gummy-stuff.org/Excel/f-curvature.xls

Excel Spreadsheet Print Version
http://www.gummy-stuff.org/Excel/f-curvature-print.xls