You want to surf the web as if, e.g., you were at your office’s network but from your computer at home. If you can access the work computer through ssh at, say, firstname.lastname@example.org, then set up a tunnel using:
$ ssh -ND 9999 email@example.com
Then configure, e.g., Firefox as follows: Preferences → Advanced → Network → Settings. Select “Manual proxy configuration”, enter “localhost” as “SOCKS Host” and “9999” as its corresponding “Port”.
Accept the new settings and, e.g., ask Google your ip address to check that it’s working.