site-C-ing is a Web development engine that uses C++ as a development language. The source code for the Web is a mixture of HTML (or whatever is the target content-type) and embedded C++. The engine preprocesses files, compiles them using the C++ compiler and serves to the user using .so shared objects. Each "component" can be considered a C++ class with the logical consequence of being able to derive one from another, etc.
siwapp is a Web application meant to help manage and create invoices in a simple, straightforward way. It can manage invoices with different serial numbers (as rectification invoices), provide printable PDF versions of the invoices with a professional look & feel, save drafts of your invoices and continue editing them later, and automatically generate invoices on a periodic basis.
sk98lin is a Marvell Yukon/SysKonnect Linux driver. In the release candidates for Linux 2.6.23, the sk98lin driver was removed under the presumption that the sky2 and skge drivers would be sufficient to cover all hardware supported by the unmaintained sk98lin driver. That presumption was wrong, as several NICs will not work at all with skge and stop talking after an indeterminate period of traffic with sky2.
skill sends signals to processes given any combination of user names, ttys, commands, and pids. snice changes the priority of processes (given the same). They are similar to kill(1) and renice(8), but the commandline is order-independent. There are also verbose, search, and interactive modes of operation.
skipfish is a high-performance, easy, and sophisticated Web application security testing tool. It features a single-threaded multiplexing HTTP stack, heuristic detection of obscure Web frameworks, and advanced, differential security checks capable of detecting blind injection vulnerabilities, stored XSS, and so forth.
skyviewer is an OpenGL-based program to display HEALPix-based skymaps, saved in FITS format files. The loaded skymaps can be viewed either on a 3D sphere or as a Mollweide projection. In either case, realtime panning and zooming are supported, along with rotations for the 3D sphere view, assuming you have a strong enough graphics card.