http://www.flickr.com/photos/vainplainjane/1557004380/ When I was a kid, we would snack on these daily. I have been recently introduced to them, and realized that none of us knew what they were called. They are larger than a grape but roughly the same shape and colour. The inside is bright green that tastes vaguely of green apple.
Hmmm... and what about the leaves, flowers? (+pics!!!) How big is the plant? etc. Looks similar to Ziziphus jujuba, but it's just a tip...
Sorry, but I don't have pics of the plant it came from. They are supplied by a local asian market where none of the english speaking workers have a name for them. They're grown locally by someone who supplies the store. Might be SouthEast Asian in origin, as that is the neighborhood and store where it comes from.
Just looked up Ziziphus Jujuba, and found reference to it being called a "chinese date." I seem to remember them being referred to as dates way back when I was a kid. 90% sure you've got it in one.