The Rπ 0 can be used as USB device and simulate serial, ethernet, MIDI, audio, human interface device (keyboard, mouse) or a combination of up to 3 of these. The combined mode does not work well on Windows and OS X.

Password management should be simple and follow Unix philosophy. With pass, each password lives inside of a gpg encrypted file whose filename is the title of the website or resource that requires the password. These encrypted files may be organized into meaningful folder hierarchies, copied from computer to computer, and, in general, manipulated using standard command line file management utilities.
On https://hackaday.io/project/9564-rpi-zero-wifi-enabled-hardware-password-manager, a Raspberry π 0 is used to run it.

Collection of software for reception of various satellite signals, ADS-B receiver (http://www.satsignal.eu/raspberry-pi/dump1090.html) for the Raspberry Pi, NTP (http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html) and more.

A Scheme / Lisp based operating system for the Raspberry Pi single board computer. Also (hopefully) provides a BSD-licensed implementation of drivers for the Pis hardware.
It used to live on https://gitorious.org/lambdapi#more, but as of 2016-02-16, it yields 404 - No projects found

Fortunately, it has been moved to github.

Case design for the Raspberry Pi.

Nice article by the Borwein brothers about efficient algorithms for the computation of pi, including

Found this page when looking for a Spigot algorithm for pi, but has also an article about using formal methods in the development of the Transputer Floating Point Unit.

One of the discoverer of new pi formulae.

Search in the decimal digits of pi.

A capability-based operating system, one of the successors of EROS (CoyoteOS seems to be another one).
According to https://sourceforge.net/p/capros/mailman/capros-devel/?viewmonth=202201 the author plans to port it ti the Raspberry pi.