gmeteor is a tool for designing discrete-time equiripple filters with linear phase and a finite impulse response (FIR). With gmeteor, you can design filters with an arbitrary frequency response. `gmeteor' runs on systems that support the Guile extension language from the GNU project (for example, GNU systems running on a Linux kernel). `gmeteor' is free software distributed under the terms of the GNU General Public License (GPL).

Java program to compute transits (conjunctions) of a satellite and sun, moon or a planet.

Smart card to securely store up to 3 keys and use them via USB for gnupg, Truecrypt and some other applications.

Instructions to enable PDF viewing in Emacs under Windows.

A slide rule which can be used in a web browser.

A company where you can have your own designs 3D-printed.

Usenet Article Lookup by Message-ID.

URDB is a universal reversible debugger that adds reversibility to almost any debugger through a python-based wrapper. URDB is still experimental. URDB supports multi-threaded and multi-process applications, as well as distributed computations. It currently has four personality modules, which support: gdb; MATLAB; python (pdb); and perl (perl -d). URDB gains its reversibility through the use of DMTCP (Distributed MultiThreaded CheckPointing), a fast checkpoint-restart package.

Another backup tool similar to Apple's TimeMachine for Linux. It appears to be based on git.

Scripting extension for Firefox. Used
<a>here</a> to make the appearance of pages more Plan9-like.