LICEcap can capture an area of your desktop and save it directly to .GIF (for viewing in web browsers, etc) or .LCF (see below).

LICEcap is an intuitive but flexible application (for Windows and now OSX), that is designed to be lightweight and function with high performance.

LICEcap is easy to use: view a demo (output is here).

In addition to .GIF, LICEcap supports its own native lossless .LCF file format, which allows for higher compression ratios than .GIF, higher quality (more than 256 colors per frame), and more accurate timestamping. If you record to .LCF, you can play back the .LCF files within REAPER (and/or use it to convert to .gif or another video format).

LICEcap is GPL free software, each download package includes the source.

The iridiumbrowser is based on the Chromium code base. All modifications enhance the privacy of the user and make sure that the latest and best secure technologies are used. Automatic transmission of partial queries, keywords, metrics to central services is prevented and only occurs with the approval of the user. In addition, all our builds are reproducible and modifications are auditable, setting the project ahead of other secure browser providers.

MTKBabel is a Perl program to operate the i-Blue 747 GPS data logger. It should work also with other GPS devices based on the MediaTek MTK chipset. Starting with version 0.7 it offers also support for the Holux M-241 data logger. It is free software released under the GPL license.

VeraCrypt is a free disk encryption software brought to you by IDRIX (https://www.idrix.fr) and that is based on TrueCrypt 7.1a.
Windows / MacOSX / Linux / Source

Just what it says. Written in c and GPL licensed.

Rtl_power is a unix-hacker's approach to the waterfall. Its unique features include:
- Unlimited frequency range. You can do the whole 1.7GHz of a dongle.
- Unlimited time. At least until you run out of disk for logging.
- Unlimited FFT bins. But in practice I don't think I've taken it above 100k bins.
- Quantitative rendering. Exact power levels are logged.
- Runs on anything. A slower computer will use less samples to keep up.

The blog has a lot of other interesting articles, e.g. http://kmkeen.com/tiny-code/, http://kmkeen.com/flash-recovery/ , http://kmkeen.com/fp/ just to name a few.

Piksi a single-frequency GPS/GNSS receiver. It delivers RTK functionality for centimeter-level relative positioning in a 53x53mm form factor. The Piksi receiver supports a high-performance, onboard Digital Signal Processor (DSP) and a flexible correlation accelerator.

Features
   Centimeter-level relative positioning (RTK)
   10 Hz position/velocity/time solutions for fast updates
   Open-source software and board design (the FPGA firmware is closed source)
   Low power consumption: 500mW typical
   Small form factor:    53x53mm
   USB and dual UART connectivity
   Full-rate raw sample pass-through over USB
   3-bit, 16.368 MS/s L1 front-end supports GPS and SBAS signals

Attic is a deduplicating backup program written in Python. The main goal of Attic is to provide an efficient and secure way to backup data. The data deduplication technique used makes Attic suitable for daily backups since only the changes are stored.
Currently Linux, FreeBSD and MacOS X are supported.

hardBackup is a powerful solution for disk-based backup on windows systems. By utilizing well proven open source technologies like Dirvish (link is external), Rsync (link is external), Openssh (link is external) and Cygwin (link is external), hardBackup can:

keep several images of backup in a rotating scheme
represent identical files in different images by one single physical copy
transfer only changes in files via secure channels

A Bash one-liner to open the source code (in Debsources) of any file on your system (if it belongs to a Debian package).