gwcalc is a front-end for the Wcalc command line calculator. Its main features are menu access to all functions defined in Wcalc, menu access to a huge number of constants defined in Wcalc, intuitive entry of formulas, easy editing and 're-evaluation', and easy conversion between decimal, hex, octal, and binary, both in input and output. It works with fractional numbers in all bases, is very configurable, and is easy to use.
yuxtapa is a multiplayer real-time CLI game. It looks like a roguelike, but feels like a multiplayer 1st-person shooter with a focus on team play. The idea is to take the "feel" of such team based multiplayer games as Enemy Territory into an NCurses-based game with roguelike controls. Like roguelikes, yuxtapa is lightweight but surprisingly rich under the crude surface. It features several classes from which to choose, each with a different special ability, randomly generated maps which can also be saved and reloaded, and multiple game modes or objectives.
ccglue is a complementary tool to cscope and ctags. The tool builds a cross-reference symbol database from cscope (and ctags) databases that can be used to display dependency-graphs (aka call-trees, code flow). Visualization can be done with the Vim CCTree plugin or the built-in stand-alone command-line tracer.