OnionCat!

The Tor software protects you by bouncing your communications around a distributed network of relays run by volunteers all around the world: it prevents somebody watching your Internet connection from learning what sites you visit, it prevents the sites you visit from learning your physical location, and it lets you access sites which are blocked.

I2P is an anonymizing network, offering a simple layer that identity-sensitive applications can use to securely communicate. All data is wrapped with several layers of encryption, and the network is both distributed and dynamic, with no trusted parties.

Freenet is free software which lets you anonymously share files, browse and publish "freesites" (web sites accessible only through Freenet) and chat on forums, without fear of censorship. Freenet is decentralised to make it less vulnerable to attack, and if used in "darknet" mode, where users only connect to their friends, is very difficult to detect.

GNUnet is a framework for secure peer-to-peer networking that does not use any centralized or otherwise trusted services. A first service implemented on top of the networking layer allows anonymous censorship-resistant file-sharing. Anonymity is provided by making messages originating from a peer indistinguishable from messages that the peer is routing. All peers act as routers and use link-encrypted connections with stable bandwidth utilization to communicate with each other. GNUnet uses a simple, excess-based economic model to allocate resources. Peers in GNUnet monitor each others behavior with respect to resource usage; peers that contribute to the network are rewarded with better service. »

Lantern allows you to give or get access to the internet through other users around the world connected by a trust-based peer-to-peer network.

Cjdns (Caleb James DeLisle's Network Suite) is a networking protocol and reference implementation, founded on the ideology that networks should be easy to set up, protocols should scale up smoothly, and security should be ubiquitous.

Bitmask is an open source application to provide easy and secure encrypted communication. You can choose among several different service providers or start your own. Currently, Bitmask supports encrypted internet (VPN) and encrypted email.

ThePirateBrowser is a bundle package of the Tor client ( Vidalia ), Mozilla Firefox Portable browser (with FoxyProxy addon) and some custom configs that allows you to circumvent censorship that certain countries such as Iran, North Korea, United Kingdom, Belgium, Finland, Denmark, Italy and Ireland impose onto their citizens.

What is CacheBrowser?