Pretty non-existent, right? Wrong! I am naturally an introverted home-body as most writers are, but having some sort of social life is beneficial for your mental and emotional well-being, and may even be helpful creatively. Being social doesn't necessarily mean being the life of every party, or even going to every party. But I still think its healthy to get a little outside your comfort zone and meet a few new people.
Don't be afraid to talk about the things your interested in, even if you think it's nerdy. Recently I met a really nice girl when we discovered we both are really into Victorian romance novels and movies, like Jane Eyre and Pride and Prejudice. (Ok, Austen isn't within the Victorian periods time frame, but her style is arguably 'Victorian'...but thats another post.) If you're a Trekkie, use it to meet people who share your interests, whether dorky or not.
Be willing to just talk to people. Join conversations. My biggest fear is usually that it will be awkward and whoever I'm talking to will think I'm weird, but you know what, I am weird, and so what. Just be yourself, and if someone has an issue with that then they're not worth worrying about anyway.
Writers can use social experiences as inspiration for characters, plot, dialogue, marketing, and lots of other things. You never know what opportunities you're missing out on when you shrink from social situations. Even getting some friends and going to a play or a movie will be both fun and creatively inspiring.
Take advantage of all the Christmas parties going on about now. This is a good time to start putting yourself out there, because people are more charitable and understanding during the holidays. So just do it and have fun!