This site covers a number of different topics and some stray things. Here’s the topics:
Everything I have online about the HP-65 calculator can be found from my HP-65 calculator page.
The information I have on the HP-67 is on my HP-67 calculator page.
There are a number of emulators for other calculators. You can find them here:
An emulator for a standard scientific calculator
An emulator for a HP-29 programmable calculator
There are also some articles on other calculators:
Move the pieces to get the picture
Freehand sketches on the go
Simple notes on the go
A basic countdown timer
None of the Above
These are the uncategorized articles
All of the Above
There is also all of the above articles.