Some downloadable statistics demonstrations
At the bottom of this page, you can download some Excel sheets to demonstrate Type 1 and Type 2 errors in a dynamic and visually-pleasing way. The .XLSM files are more interactive (with a button!), but you'll have to enable macros (a banner at the top of the sheet) to get them to work. If the idea of downloading a macro-enabled Excel file from the internet appalls you (as well it might), you can download the macro-free variants. These work just as well, but the re-sampling is a bit clunkier (instructions at the top of all files at any rate.