Puppy Linux is a Linux distribution that is about 100 megabytes, yet it includes a complete set of graphical applications, combined with extensive utility applications. Puppy was created from scratch, file-by-file, optimized for size at every step. Another feature of Puppy Linux is that it can work totally without a hard drive, even allowing you to save data and install extra packages by saving back to the CD or DVD.
VoiceBuntu (formerly Ubunterisk) is an Ubuntu-based live CD that uses Asterisk and VoiceOne to provide VoIP service without any system installation process. VoiceOne is a Web-based GUI for the Asterisk PBX. Ubunterisk can be used as a phone client as well as a PBX server. Ubunterisk can be administered either remotely or by accessing its local GUI. A capser-rw filesystem is used to store the system's data persistently.