Today I've stepped over a nice function of SSH: the -D parameter. Compared to a tunnel to a single host using the -L option, -D can provide a proxy for all traffic. Lets make an example:
If you own an SSH server (with the address "host" in the example) and want to use it as a proxy, establish a tunneling connection using the -D parameter:
sudo ssh root@host -v -D 5000
Now lets say you want to tunnel your webbrowsing using Firefox through your server "host", go to Firefox' "network preferences" and "connection settings". There, enter localhost as socks proxy using port 5000:
After doing this setting, you should be able to browse to http://whatismyip.com or equivalent page, and it should display your server's IP address, meaning that the traffic is tunneled through it.