GNU Wget is a utility for noninteractive download of files from the Web. It supports HTTP and FTP protocols, as well as retrieval through HTTP proxies. It can follow HTML links, download many pages, and convert the links for local viewing. It can also mirror FTP hierarchies or only those files that have changed. Wget has been designed for robustness over slow network connections; if a download fails due to a network problem, it will keep retrying until the whole file has been retrieved.
UAE is a mostly complete software emulation of the hardware of the Commodore Amiga 500/1000/2000. A Commodore Amiga, for those who don't know, is a 16/32 bit computer system based on the Motorola 680x0 CPU and a few specially designed custom chips that provide very good graphics and sound capabilities. Its first incarnation, the A1000, appeared in 1985, followed by the highly successful A500 and A2000 models. But if you didn't know, you probably don't want an emulator.
Freeciv is a multiuser reimplementation for Unix/X of the famous Microprose game of Civilization. By default, the game is an improved Civ II, but this can be customized; modpacks for near-100% compatibility with Civ I and Civ II are included. Multiuser gameplay is real-time: in each turn, all human players move concurrently. The game is designed to remain fairly playable even on poor network connections. Freeciv can also be played on standalone machines, and its AI players are a good challenge for beginners. The source code comes with the server, two X clients, and non-X clients for MS Windows and Amiga. Freeciv is released under the GNU General Public License. It is maintained by an international team of coders and enthusiasts, and is easily one of the most fun and addictive network games out there.
RealPlayer plays streaming audio and video over the Internet in real-time. It plays RealAudio, RealVideo, MP3, 3GPP Video, Flash, SMIL 2.0, JPEG, GIF, PNG, RealPix, RealText, Ogg Vorbis, and Ogg Theora. It is available for Windows, Macintosh, Pocket PC, Nokia 9200 Series, Nokia 7650, Palm OS 5-based handhelds, Linux, Solaris, and many Unix variants.
rsync is a replacement for rcp (and scp) that has many more features. It uses the "rsync algorithm" which provides a very fast method for remote files into sync. It does this by sending just the differences in the files across the link, without requiring that both sets of files are present at one of the ends of the link beforehand.
Sajber Jukebox is a mpeg layer 3 player with a graphical user interface. It's based on Woo-jae Jung's splay for the audio and QT's graphical library for the interface. The Jukebox maintains pointers to songs on the local system or the net, and when the user wishes to play it, it opens the location and migrates the filedescriptor to the playing process. The advantage of this scheme is that the Jukebox doesn't need to worry about playing the darn thing, and the player won't have to worry about where the song is, since it'll just see the filehandle given to it, and couldn't care less of where it originally came from.