Power PC: 
Native Mode
Hold down Command and Shift when getting info. on a native Power PC application.  You will then see a list of credits of those who provide native mode. This may not apply for system 7.5.1.

Graphing Calculator "NuCalc"
Turn on Balloon help and go to "About Graphing Calcucator...".  Then click the "Credits" Button.  There you want to simply drag the mouse over the window containing the credits.  Go to the next page and drag the mouse over both sides of the window.  Also, Balloon help the CSC button in the full keypad to see at the bottom "c.f.E. Rutherford, Phil.  Mag. 21, 669 (1911)".  I believe this is the nuclear physicist (also known as Baron Rutherford) who, in 1911, worked out the nuclear theory of the atom.  Finally, drag balloon help over the application itself.

Here is an interesting undocumented trick.  The Graphing Calculator also
works with a number of word processors as an equation editor: copy an equation from the Graphing Calculator and paste it into the word processor, then later double-click or command-double-click, I don't know which, on the equation in the word processor, and it will launch the Graphing Calculator, and allow editing of the equation.  I think this works with MacWrite Pro, WordPerfect, and a few other word processors.