I experienced the Grey Box Theater as a venue for the Dress for Success fundraiser. it is a fun space in Lawrenceville that can be rented to host special events, parties, fundraisers, concerts, etc. It was a neat space that can easily be used for a variety of things (as is evidenced by the fact that it apparently previously hosted a cat circus...). Even though it is a "theater" there is no stage which makes it a versatile space. We were able to set up seating for a panel discussion and guests along with cocktail tables. There was also a great deal of lighting options which can really add ambiance to your event. They also allow you to bring your own food and drinks which is a plus since a lot of venues lock you in to a certain caterer or don't allow outside items.
The down side is that if the event is during the day, you need to find on street parking which can be a challenge in Lawrenceville.
Overall a great space for a smaller special event.