1. Install open ssh server on your home machine and leave it connected to internet.
In Ubuntu, open a terminal and:
sudo apt-get install openssh-server openssh-client
To start the server:
sudo /etc/init.d/ssh start
and to stop it:
sudo /etc/init.d/ssh stop
3. From work / school, enter this command:
ssh -D 2345 ipaddress _of_home_machine
You can replace 2345 with another port, it's just an example! Also, replace ipaddress _of_home_machine with... well, you got it, your home machine IP :)
Now open an application you wish to use to get pass the restrictions, let's say: Firefox. Open your Firefox browser and select Tools (or Edit for Linux) > Options (or Preferences for Linux) > Advanced tab > Network > Settings. Fill in 127.0.0.1 against the Socks host column and enter 2345 as port. That's it.
If you want to do this with Windows being either one of the computers, use OpenSSH for Windows which comes with both a server and a client.
[via unixlab]