I was using up some aging watercress in a salad the other night, which reminded me of a simple trick for crisping wilting greens: Soak them in ice water for a few minutes. The ice bath rehydrates their cells and they perk right up, crisp as the day they were harvested. (Just make sure to drain and dry the greens well before using, or the dressing won't coat the leaves.) This'll work with any salad greens or herbs, or limp veggies like older celery and carrots.
Photo: Courtesy of Miky Jpeg at Flickr