I had it...I know so bcs after I installed Ubuntu, a bunch of things were downloaded, like updaters... I was also chatting on IRC and had surfed around a bit with Firefox.
Then, I lost the chat connection and Firefox won't get out of offline mode. I have another machine connect to the same router and internet connection (typing on it right now) and it has internet.
Since I'm pretty new to Ubuntu (as in 2 hours new) I don't know how to restore the internet connection, or even where to start looking.