MiniKnoppix is a all-in-one sysadmin rescue CD.
Basically it is a complete and totally functional GNU/Linux operating system that boots and works from the CDROM. This way there's no need to install it on the hard drive.
Knoppix is (possibly) the best Linux Live CD nowadays. The original version fits in a 74 minutes (650MB) CDROM and carries more than 900 software packages ranging from office applications, development tools, multimedia players, games, different desktop environments and almost anything you can think of.
MiniKnoppix is born out of the 'necessity' (some of us have) to carry a GNU/Linux operating system everywhere. Knoppix fits in a standard CDROM that you can carry in a rucksack, a suitcase, in your car,... But it is not so 'wearable' for the daily use. MiniKnoppix takes up 200MB and can be toasted in a 8 cm. CDROM. So you can carry it in your wallet, which is its goal.
MiniKnoppix is JUST Knoppix WITHOUT a HUGE amount of software. To sum up, MiniKnoppix does not have games, development tools/libs, most of the multimedia players, office tools,... MiniKnoppix has only one graphical environment (KDE), its browser (konqueror), mail, web and news text based clients (mutt, slrn, links) and lots of tools for system administration (backup/restore, filesystem check/creation, security, network testing, and more!).