GeeXboX is a standalone media player Linux distribution, similar to MoviX. It's a small bootable CD that allows you to play your favorite video (DivX, XviD, H.264, MPEG 1/2, VCD, DVD, OggMedia, Windows Media, RealMedia, etc.) and audio (MP3, Audio CD, Ogg Vorbis, FLAC, MPC, etc.) files. It also supports networking, and is able to play media from Windows/Samba share, NFS, UPnP A/V Media Servers, RTP/RTSP servers, or SHOUTcast. It supports TV-out, TV tuners, DVB cards, and WiFi cards. It is based on MPlayer, and can be used on any x86, x86_64, or PowerPC computer. It's easy to modify the source to build your own GeeXboX or use an alternative boot method.
PlumpOS is a bootable openMosix node on a CD. Pop the CD into a 486+ computer and you have an instant openMosix node. It supports loading 3rd-party packages and adding custom kernels. It takes up very few resources. It was originally a clone of clump/os, but has evolved into something that doesn't resemble it much anymore.
YES Linux is a server appliance for small and medium size networks to quickly and easily build an Internet presence. It completely installs in under 10 minutes and 2 screens. It features a secure Web server, a secure email server with Web-based email, a firewall, spam filtering, WebDAV support, an FTP server, an SSH server, a PostgreSQL database, the Resin J2EE server, Java, Apache Ant, PHP 5, Autonomous Backups, and complete Web-based administration.