It doesn't sound that great, but has health benefits, especially for singers.
(A surprisingly fresh tasting, good for you drink.)
In a 2 quart pitcher or bottle, 1/2 cup of organic apple cider vinegar (the good kind you get from a health food section)
Add 4 droppers of liquid stevia (available from Vitacost). Or, you can sweeten it with about 3/4 c honey dissolved in hot water.
Optional: One package of "Emergen-C". (I use Super Fruit, Triple Berry Burst). Add water to fill the container.
Divide that mixture into two separate 2 quart containers. Add 2 cups of light grape juice (or apple juice or other juice) to each container.