nscache is a simple program to browse the Netscape cache directory with a GTK UI. It shows the contents of the browser cache in a three level hierarchy of files: protocols, servers and documents or in sorted list. nscache permits you to view files from the cache, remove files, or gather various information about specific files.
nwfiir and its accompanying software wfird allow design and use of a HiFi quality digital equalizer based on a WFIR filter (Warped Finite Impulse Response). It can take advantage of multiple processors, e.g. on a dual Pentium II 300 MHz it manages to run a two-channel equaliser with 275 taps, with 16 bit 44.1 kHz input, and 24 bit 44.1 or 88.2 kHz output. This is more than enough to very precisely equalize the whole audible range from 20 to 20000 Hz. The equalizer can be used as, and was designed for, a key component in a room equalization system. Non-realtime operation is also possible on slower machines.
Obsidian is an extensible virtual world system with a fullblown multiplayer client-server architecture. It is not a VRML2 world system, though there are plans to include VRML2 as a world data format. Note that active development on this system stopped a while ago, though the code is still available for the curious. The code may not even compile on current Linux or Irix systems.