German potato salad is the best potato salad in the world. It's sour and sweet and wonderful. And best of all - NO MAYO! :D
(Mayo is the worst. Remember that.)
German potato salad is great hot or cold, and it's really easy to throw together. I'm using the recipe from Joy of Cooking, but slightly altered so it's more like my grandmother's. Her German potato salad had whole mustard seeds and no celery, so that's the way I make it too.