Milk?
Sometimes leg cramps can be caused by vascular issues, sometimes they're neurological in nature, causing the muscles to cramp up.
They make over the counter meds such as Q-vel (I think that's what it is) -- it's quinine. (Or you could just drink tonic water!) But quinine (PROVIDED YOU ARE NOT PREGNANT!!) has been used for ages for leg cramps.
Also, adequate intake of magnesium -- it is a muscle relaxant. In fact, magnesium is given to birds in captivity when giving difficult births to ease contractions. One of the best forms I found was a powdered calcium/magnesium combo that you just added to hot tea! It was amazing, and it also was very soothing and calming. It worked great.