The RegLookup project is devoted to direct analysis of Windows NT-based registry files. RegLookup provides command line tools, a C API, and a Python module for accessing registry data structures. The project has a focus on providing tools for digital forensic examiners (though it is useful for many purposes), and includes algorithms for retrieving deleted data structures from registry hives.
net-status-monitor is a simple console script to test whether Internet connectivity is working. If it is, the script tells you the external IP address (in case your dynamic DNS provider is down). If not, it tries to find the point where the connectivity fails. The output is quite simple, so you can put it on your grandmother's PC. "Just tell me what the read line says" should give you enough information.
Lynis is an auditing tool for Unix (specialists). It scans systems to detect software and security issues. Besides security-related information, it will also scan for general system information, installed packages, and possible configuration mistakes. The software is aimed at assisting automated auditing, software patch management, and vulnerability and malware scanning of Unix-based systems.
Python Tracer lets you see your Python program's execution as a tree of function invocations, each tree node exposing the real time and CPU time (user/sys) of that call. The project consists of two main components: a Python tracer that can run your Python programs (much like "cProfile" and friends), and a GTK+ based GUI that can show the trace results. It uses a tiny auxiliary library (graphfile) to allow append-only writing and reading static DAGs directly from a file without reading it whole into memory at any stage.
UnusedPkg is a diagnostic tool to search the oldest unused packages in your Linux system. UnusedPkg prints a sorted list with the size and number of days that a package has been idle. This helps you determine what packages can be manually removed to clean the system. It supports any apt-based distribution (tested on Debian and Ubuntu) and Slackware.