By far the most popular project is the stackless python tutorial.  I still get questions about stackless to this day.

pyASM is a dynamic assembler for python, meaning you can generate and execute assembly code at runtime.  It somehow got my name up on CiteSeer.  That's scary!

Compyler was my pre-alpha attempt to write a native compiler for python code.  It can actually compile some simple python code.  The goal was to have all the speed of python and all the safety of raw assembly.

PyXR created hyperlinked browsable versions of python code, similar to the lxr, although all code was written independently.  I thought it was pretty useful, but no one else seemed to.