Drink, talk, play games, share music. If I don't know many people, it's normal for your friends to be socialising with a bunch of other people they know. I usually grab a beer, look for two or three friendly people sitting down, have a sit, tell them my name, and tell them I know no one except that guy surrounded by a bunch of strangers. Almost always they're friendly back, start asking questions about me, I ask question about them, and soon enough we've reached a common ground or some topic we can talk about.

If I'm ever stuck alone again, I can seek them out like, "Yup, it's happened again so I'm just gonna hang around you guys so I don't feel weird." And that's always quite a laugh.

Extroverts are your best friends in these situations. Most love leading the conversation and appreciate you seek them out. They'll take care of you. It's not awkward at all.