strace is a system call tracer, i.e. a debugging tool which prints out a trace of all the system calls made by another process/program. The program to be traced need not be recompiled for this, so you can use it on binaries for which you don't have source.

Spring is a modern full-3D RTS (Real Time Strategy) game engine originally created to bring the gameplay experience of Total Annihilation into 3D. Games are played using one of a number of mods.

A free environment for regular expression testing (ferret). It allows you to write regexes and test them against a sample text, providing extensive output about the results. It is useful for several purposes:

This package provides simple commands designed to be used with a minimalistic window manager like dwm but they can be useful in scripts regardless of the window manager used.

Csound is a sound and music synthesis system. Drawing from over 450 signal processing modules, it can be used to model virtually any synthesizer or multi-effect processor. It can work either in real-time or as a compiler.

Links is a text mode WWW browser, similar to Lynx. It displays tables, frames, downloads on background, uses HTTP/1.1 keepalive connections.