Especially during the holiday season, it's very likely that companies will host a social event outside of work hours. This could be at a restaurant, bar, or even a co-worker's house. These events provide great opportunities to get to know your co-workers on a more personal level. If you haven't already gotten to know some of them beyond their name and job position, here's your chance. Forget about projects and due dates; no one really wants to talk about that during their off hours.
Oh, and one more thing. Wherever the social gathering is held, there's likely to be judgement impairing substances such as... alcohol (gasp!). It's ok, don't worry. I'm not going to go all Lifetime Special on you and tell you that drinking is bad and if you drink you will get pregnant and die. But if you don't know how many drinks it takes to lose your composure then I hope I don't have to remind you that now is a bad time to find out. If you know your limit, then good, stay under that. If you don't know or if you're a light-weight, you might want to limit yourself to no more than one drink and drink it slowly. And, of course, if you're under the legal drinking age (mostly important in the US where that age is 21) then stick to non-alcoholic beverages (sorry, my friends, but it is the law).
Also make sure you are dressed appropriately. Find out in advance what the expected attire is. If you're going to a public place, you can probably judge what to wear based on its atmosphere. Even if the venue is really relaxed, it's still a good idea to dress a bit modestly: keep midriff, chest, and thighs covered.
Basically, my advice is to get to know everyone and enjoy yourself but remember you will still have to face these people the next morning and you may want them to write recommendations for you later.
Katie Hazard | Digital Artist, User Experience Designer
firstname.lastname@example.org | @katie_hazard