If the switch inside the headphone port is staying on, there is a workaround that I've discovered. Take an old pair of headphones and cut the wire just above the male connector that gets inserted into the port, and insert the jack into the sound port. Open up System Preferences and go to Sound. Under the Output tab, click to highlight "Internal Speakers". At the bottom of the preference pane where it says "Use audio port for", change the drop down to read "Sound Input". This will force the sound to come out of your built in laptop speakers. Note that this will disable your built-in mic, so this solution will not work if you need to use Skype or any other application that requires your mic and speakers to function at the same time.