Just because Digital Media Minute is a friend of the little guy (who finds it inconvenient to not have Facebook open all day at work), here is the simplest possible workaround to bypass internet filtering if your employer is filtering specific sites: just add an ‘s’ to the http line and you might find access to the secure version of sites when there was no access to the standard version.
Caveat: your employer might be filtering sites by way of keywords, in which case this method won’t work. At any rate, even needing to beat internet filtering on your work computer may be less relevant moving forward as we increasingly do our own thing on our own devices, but until then an internet filtering bypass like this could come in handy. (h/t Lifehacker)