This is the first Google Apps Script that I've substantially written myself (and I am just beginning to learn Javascript), so the code is probably very ugly and inefficient other than the libraries I borrowed from the Google Apps Script tutorials.  Please let me know if you can find a better way to accomplish the same thing.

1) Copy the spreadsheet template

2) Create a new page on your Google Site that is visible to your students and their parents (via link only?) where you want to install the per-student progress chart.

3) Install the attached script via "Manage Site" and authorize all visitors to run it.  This will prompt anyone with a regular Gmail account to log in via their domain account when they visit the dashboard page.

4) Modify the script, adding the correct (new) spreadsheet key from the copied spreadsheet you created and any other values you wish to change.

If you want to add more columns and rows to the sample spreadsheet, don't forget to expand the defined range "studentlookup" from the "Data->Manage Ranges" option .  If you add more columns, the bar chart will automatically expand to include them, with the column headers as labels.

You can keep the spreadsheet private and the values will still chart in the Sites page, but only for the correct, logged in user!