"pfSense is a free, open source customized distribution of FreeBSD tailored for use as a firewall and router." pfSense is a fork of m0n0wall, and uses pf, openBSD's stateful packet filter.
... 
"grml is a Debian-based system administration distro, providing more than 1700 software packages. "You'll get sysadmins favourite tools, security- and network-related software, data recovery- and forensic-tools, LaTeX, many editors, shells, and of course many texttools."
... 
Sabayon is a Gentoo-based GNU/Linux distribution with support for binary package installation. It is, therefore, more of a hybrid distribution than a purely source-based distribution like Gentoo. That is another way of saying that you can install a Gentoo-based distribution without having to compile packages from source. While most Linux distributions follow a 6-month release cycle, Sabayon bucks the trend by making new releases available for download at about half that time.
... 
"CentOS is an enterprise-class Linux distribution derived from sources freely provided to the public by a prominent North American enterprise Linux vendor. CentOS conforms fully with the upstream vendor's redistribution policy and aims to be 100% binary compatible. (CentOS mainly changes packages to remove upstream vendor branding and artwork)."
... 
Ubuntu Desktop is a Linux distribution derived from Debian. It is one of the most popular (Desktop) Linux distributions available, and many other distributions are derived from it. Development is sponsored by Canonical. There are two editions of Ubuntu Desktop - Ubuntu Desktop and Ubuntu Desktop Alternate Installer. The only difference lies in ...
Fedora is an RPM-based Linux distribution. Development is sponsored by Red Hat, Inc. It is one of the so-called major distributions, and out of the box, does not have non-free application installed.
Fedora's installer, Anaconda, is used by several other Linux distributions, and features many enterprise features that is not available on other distributions installation programs.
... 
"KNOPPIX is a bootable Live system on CD or DVD, consisting of a representative collection of GNU/Linux software, automatic hardware detection, and support for many graphics cards, sound cards, SCSI and USB devices and other peripherals. KNOPPIX can be used as a productive Linux system for the desktop, educational CD, rescue system, or adapted and used as a platform for commercial software product demos."
... 
Zenwalk is a GNU/Linux distribution optimized for the i686 instruction set, but backward compatible with i486. It is based on Slackware Linux, and uses Xfce as the default desktop environment.
... 
Android is a Linux-based operating system for mobile platforms developed and maintained principally by Google. It now powers a number of smartphones currently in the market including Google's own Nexus One, and several handsets from Motorola, Acer and other members of the Open Handset Alliance. The platform was announced to much fanfare in late 2007. Here's a video introducing the latest version of the platform.
... 
SystemRescueCd is a Linux distro designed for repairing your system and your data after a crash. It ships with dozens of software packages used to carry out admin tasks on PC, and it's usable on x86, SPARC, and PowerPC (Mac) architectures.
... 