I went to this last year and it was fantastic, over 300 cars that time, trying to break 400 this year. Great food, music, and a gift bag if you show your car. Just email Bruno @ firstname.lastname@example.org and say you'd like to attend and what car you'll be bringing. Once you join you'll get updates on other get togethers throughout the year, which are also lots of fun.
I've been to a bunch of car shows in NY/NJ/CT and they tend to be mostly hot rods and muscle cars, but this one is all exotics, the most I've ever seen in one place. I'll be driving a Maserati GranTurismo Sport, if you have an exotic, don't be afraid to show it, it's a very well organized event, and you're not obligated to stay for the entire time. You also don't have to enter your car in the Concours unless you want to. And if you just want to come see all the cars, music and food, it's free admission.