Trinux is a small ramdisk/floppy based Linux distribution that contains useful tools for mapping and monitoring TCP/IP networks (i.e. intrusion detection and vulnerability scanning)
Tiny linux distro with howto that runs solely on ramdisk, boots from CD, network, or USB, is less than 40MB, and works as a server/router with many different servers (Apache web, ssh, ftp, telnet, etc). Minimalized from Fedora Distribution.