Contrary to popular geek belief, ancient Egyptians did not write on PyPRUSS. But if they'd known Python, they might have.
Actually, the oldest thing about PyPRUSS— a Python library for the PRUs—is that it was primarily focused on the earlier Angstrom firmware for the BBB, a distribution now looking increasingly mummified. Which is not to say that PyPRUSS does not still remain a great userland touchstone for Pythonistas and PRU-ophiles.
In fact, even though there is no pre-compiled binary in the Debian repositories for PyPRUSS, it takes all of 90 seconds to compile and install from source, and begin running Python on the PRUs quickly.
The usual minimal setup is all you need: a BBB powered over mini USB with Internet connectivity. You will also need to have done the first recipe in this section on prepping and enabling the PRUs.