Weird fruit

One of the farmer's market vendors had this weird fruit that Brian and I picked up on Saturday. I tried one last night and I really loved it. They look a lot like green grapes but have thin vertical stripes from end to end. It tastes a lot like a SUPER bitter green grape but the name given was definitey not grape. There's bits of stem on one end (like a grape) and a kind of thread-thin trailing tail (only way I can think to describe it). Its something growing in the Metro Boston area now.

Any ideas? If I heard the name I'd recognize it but I can't for the life of me remember it (and google isn't turning up anything)!