Tails
The Amnesic Incognito Live System (Tails) is a Debian-based live DVD/USB with the goal of providing complete Internet anonymity for the user. The product ships with several Internet applications, including web browser, IRC client, mail client and instant messenger, all pre-configured with security in mind and with all traffic anonymised.
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Puppy Linux
Puppy Linux is yet another Linux distribution. What's different here is that Puppy is extraordinarily small, yet quite full-featured.