You press on a grape and you get wine. Press harder and you get grapeseed oil. The oil is actually made from pomace, a by-product of the winemaking process. It contains the stems and seeds (sounds like your last bag, doesn't it, bones?) and skins of the grapes.
Apparently, this grapeseed oil is becoming the big thing with chefs. It's a good source of vitamin E and linoleic acid. Linoleic acid is an essential fatty acid that some nutritionists think reduces blood clotting and inflammation. The oil is low in saturated fat. It has about 9%, compared to olive oil's 14%.
It's good for sautéing because its smoke point is 485°. Some chefs use it to make mayonnaise, vinaigrettes, and to cook fancy seafood dishes.