Dried fruit - pineapple rings, mango, figs are all good. Cream cheese and jelly sandwich - yum!
Make your own sports drink, too - add a couple of spoons of sugar and a splash of lime juice to a full water bottle, shake and voila. In the summer I sometimes add a pinch or two of salt. Works about as well as expensive powders like HEED, tastes as good or better, costs a fraction as much.