PAX is pretty much what E3 used to be, but open to the public. The first year they did what is now PAX Prime in Seattle, the tagline was something like "Spend the weekend with 30,000 of your best friends". Although PAX East is closer to 70,000, it remains true.
There are panels with developers, and an expo hall to try out new games (the big demo lines last year were for Portal 2, Duke Nukem Forever, Battlefield 3, the 3DS, and SWTOR, for example). There's an arcade room, a LAN party with 300 people, an area for tabletop gaming, and a handheld hallway, where you can just drag a bean bag chair over to a new group of people and have a Mario Kart race or battle Pokemon.
Even in line for the panels last year, I had fun. People in front of or behind me would be playing some card game and just ask if others wanted to join in. Or they'd have their DS out and be sending messages out on Pictochat.
I know it sounds like an idealistic place, and I am glorifying it a bit, but waiting for the Keynote speech to start last year, I pulled out my DS and Pokemon White (which had only been out about 2 weeks at that time). I turned it on and told my husband that I was going to see if there was anyone else to connect to for the survey mini-game. He laughed at me...until I immediately connected with 140 other people, just in the Keynote theater. It's safe to say you do feel like you're among friends.
