Finnix
Finnix is a Debian-based Live CD operating system, developed by Ryan Finnie and intended for system administrators for tasks such as filesystem recovery, network monitoring and OS installation. Finnix is a relatively small distribution, with an ISO download size of approximately 100 MiB, and is available for the x86, x86-64 and PowerPC architectures, and paravirtualized (User Mode Linux and Xen) systems. Finnix can be run off a bootable CD, a USB flash drive, a hard drive, or network boot (PXE).
Read more about Finnix.