audiopreview is a command-line tool that plays previews of many audio file types (Ogg, MP3, etc.), video file types (AVI, MPEG, Real, etc.), and Internet streams. It can also be used as a regular command-line media file player (i.e. play the files entirely like yauap or mpc123 would).
Cdarts is a low level implementation of a computer darts player. It can be used as an opponent against a human in the game, or it can be used as a simulator for fun. It currently supports only two different game types (301 and 501), but can be extended to support more games. It supports three different levels: beginner, hobbyist, and professional. Each level tries to simulate a human at that level as well as possible.
Minix editline is the line editing library from Minix, originally created by Simmule R. Turner and Rich $alz in 1992. It can be linked into almost any program to provide command-line editing and history. The editline library is call-compatible with the FSF readline library, but is a fraction of the size and offers fewer features. It is distributed under a "C News-like" copyright; see the file LICENSE for details.
Binmay is a command line binary search and replace program. It allows one to specify a binary string (in hex) to search for and, optionally, a binary string to replace it with. One can mask both search and replace strings as one can mask an IP. It is handy for changing broken user SID/RIDs in ntuser.dat files after you move a profile from somewhere to somewhere else.
Dateutils are a bunch of tools that revolve around fiddling with dates and times in the command line, with a strong focus on use cases that arise when dealing with large amounts of financial data. Their target market is shell scripts that need date calculations or calendar conversions, and as such they are highly pipe-able and modeled after their well-known cousins (e.g. dtest vs. test, or dgrep vs. grep).