Do you mean the Pin Trading Night that happened last night, or the big one in September? I'll cover both, just to make sure I answer all questions...
Pin Trading Nights are usually every two months (they used to be once a month, but I think they cut back due to staffing and scheduling issues). Usually at the Contemporary ballrooms. They're free, and are mostly rows of tables for trading. They last 3 hours, and parking is free. You just tell the cast at the gates that you're going to the Contemporary, and they'll let you through. Bring your ID, because I've had a friend turned away at the gate for PTN when she left hers at home.
No registration required, and like I said, it's free, as well. Line-up starts at a stupid hour, IMO. It usually starts at 6 PM, and people line up as early as 3 PM- for no reason that I can see except maybe to have the best table space (I usually walk instead, so I don't need that). I was able to walk up and buy every pin I needed after the new release line died down, but I know some pins have sold out before.
The major pin trading event is in early September (usually).
This year, it's called Mickey's Circus, but the theme changes every year. It's a 4 day event- a full pin trading day PLUS early registration/pin pick-up is on Thursday (usually at a Disney hotel). The pin event is Friday and Saturday, and Vinylmation event (with a separate fee) is Sunday, all in EPCOT. You do need to pay to get into the park if you don't have an annual pass of some kind.
Parking is either paid for with your annual, if you have one, or you have to pay (I think it's stupidly high now, like $12-$15. Or you could always park for free at the Boardwalk, then walk in through the International Gate entrance. I never pay for parking at Disney.
Pin event is usually around $100- you get some gifts and a $30 Disney gift card with your registration.
They do have pins made exclusively for the event. When you register, you get to submit a lottery-like form called a RSP (Random Selection process). You pick which pins you want the most at the top of your form, then list them down. The computer will select who gets first dibs at purchasing them. They do this so we're not standing in line all weekend to get the most desired pins- gives everyone a fair shot at things like LE 100s and such. We usually submit the forms by July something, and then hear the results by mid-August, so we have a chance to return them and see what we won the chance to buy.
Times are usually from 9 AM - 6 PM.
They have some special things you can buy as well, like breakfast and dessert socials.
The info is still up at
www.odpt.com if you want to read it over- registration is still up, if you want to try for it.
We don't usually have other major events at WDW, but occasionally, they'll surprise us with one- Love is Magical was a surprise February one-day event a few years back.