Grml

grml is a bootable CD (Live-CD) originally based on Knoppix and nowadays based on Debian. grml includes a collection of GNU/Linux software especially for users of texttools and system administrators. grml provides automatic hardware detection. You can use grml (for example) as a rescue system, for analyzing systems/networks or as a working environment. It is not necessary to install anything to a harddisk; you don't even need a harddisk to run it. Due to on-the-fly decompression grml includes about 2.1 GiB of software and documentation on the CD. You don't have to pay anything to use grml because it is free software!