When the farmers market are loaded with these purple jewels and you're not sure what to do with them, try making grape jelly. The first time I did it, the house was filled with the most nostalgic smell of bazooka bubble gum and my grade school PB&J sandwiches all rolled up in one. For a novice jam or jelly maker--this is a great place to start. There is so much pectin (the thing that makes it gel) in these babies that it's not necessary to add any of the gross artificial stuff.
Here's the formula: 4lbs grapes (you want 4 cups juice). Wash (really well) and cook the fruit to release the juice, about 10-15 minutes. Drain through a jelly bag (I used an old flannel sheet). Measure the juice, to be safe and bring it to a boil. Reduce heat and stir in an equal amount of sugar (I use organic cane sugar) but don't let it boil again--just cook until the sugar is dissolved and is has thckened slightly. The color will turn into a deep purple. Ladle into clean jars. Cool, top and refrigerate. I don't bother processing it since it lives in the fridge and is used up so fast for toast, sandwiches, sauces for pork, duck etc.