Mmm, dark chocolate with yogurt-covered pretzels, rainbow sprinkles and salty potato chips. Or—oh, God—milk chocolate with pumpkin seeds, dried raspberries and flaxseeds. No—wait—white chocolate with toffee bits and Fruity Pebbles. Hungry? Sites like Chocri.com, Chocomize.com and ChocBite.com let you customize your own bar from scratch, with scores of sweet, savory and spicy add-ons. Chocolate with Pop Rocks, anyone?