I get this on my vine each year... Grapes on bunches that are smaller than the rest. They seem to taste just as good as the larger grapes on the same bunch, just not as appealing. Try one and see.

you could make wine or grape juice or stilol eat them as Myron sais .

other than eating them I can't imagine what you could do with that quantity. If that is your entire crop and they don't stand eating then I would suggest getting rid of the vine and planting something that takes less effort.