You know you're at the Penny Arcade Expo when you see princesses in full regalia rubbing shoulders with giant-eared elves and gun-toting space marines.
You know you're at the Penny Arcade Expo when you see throngs of people lined up to get their photograph taken with a zombie ... or see them joking around with a walking, talking mushroom.
You definitely know you're at the Penny Arcade Expo when you see Star Wars Stormtroopers dancing to klezmer music.
That is to say, you never know what you might see at the annual gaming extravaganza more commonly known as PAX Prime.
PAX Prime is an annual convention under way in Seattle this weekend. It's an event that has drawn some 70,000 gamers from around the world to the Washington State Convention Center to celebrate gaming in all its forms.
It's here that video game companies large and small show off their latest projects, giving gamers a chance to get their hands on forthcoming titles months and sometimes years ahead of their launch. ("Borderlands 2," "ZombiU" and "Dishonored" are just a few on display this year.)
But PAX is more than that. Much more. Here you'll find gamers gathered together playing tabletop and card games like "Munchkin," "ZoxSo" and "Ninja Versus Ninja." You'll find them trying their hand at old-school arcade games like "Ms. Pac Man" and "Donkey Kong." And you'll find rooms full of players laser-focused on high-end PCs as they compete for bragging rights and real-world loot in games such as "League of Legends" and "Dota 2."
You'll also find gamers attending dozens and dozens of panel discussions on topics such as how to break into the games industry, how to raise young geeks and gamers, and how make game-related costumes and other handmade geeky goods.
The creators of the Penny Arcade web comic -- Mike "Gabe" Krahulik and Jerry "Tycho" Holkins -- started the Penny Arcade Expo back in 2004 to give gamers a convention of their very own (see InGame editor Todd Kenreck's video below for more on that). The event has grown so popular (not to mention so big) that in 2010 they started PAX East in Boston. And this year, demand for PAX Prime tickets was so high they sold out in less than 24 hours.
And now PAX is going international for the first time. Krahulik and Holkins on Friday announced that they will host a Penny Arcade Expo in Australia starting next year. Meanwhile, PAX Prime in Seattle will grow from a three-day event to a four-day event starting next year.
So why has PAX become such a mecca for gamers? As the people who attend the event year after year will tell you -- while conventions like the Electronic Entertainment Expo in Los Angeles are focused on the business of gaming, the thing that makes PAX special is that it is all about the players themselves. It's a three-day celebration of everything that is awesome about playing games and being a gamer. And it is designed to be a welcoming place for the many different elements that make up the gaming community at large.
"PAX is the thing I look forward to the most because it's home to me," said Stephen Toulouse, an avid gamer and former director of policy and enforcement at Xbox Live, as he opened a talk about treating each other well in online games. "You are my people."
"The heart of PAX is about bringing people together who play games," said Amanda Wan, who arrived at PAX dressed up like the character Riven from "League of Legends."
She has been coming to PAX for six years and says that, yes, the event has gotten far more epic. But she pointed out, "They've stayed true to the purpose of bringing gamers together."
And what, exactly, happens when you get 70,000 gamers together in one place?
Stormtroopers dance. Zombies pose for photos. Elves, princesses and space marines all live happily together.
"Everybody just gets together, nerds out and has a blast," explained Alli White, who drove to Seattle from Rathdrum, Idaho, just to attend the event. "It's just all-around awesome."
Winda Benedetti writes about video games for NBC News. You can follow her tweets about games and other things on Twitter here @WindaBenedetti, and you can follow her on Google+. Meanwhile, be sure to check out the IN-GAME FACEBOOK PAGE to discuss the day's gaming news and reviews.