playing in litter box

my cat is a little over a year old, is all he does is play in his litter box. He has toys everywhere and food all the time but when were just sitting there watching tv the cat will just walk over to the litter box and dig. he flicks litter everywhere and makes a huge mess most of the time he doesnt even use the litter box he just sits and digs. i have no idea how to make him stop and i have looked all over the internet for articles on it and i have found nothing. What should i do?? I cant get him to stop.... HELP!!

Is the cat going potty elsewhere? Is he indoor/outdoor? There isn't enough information to comment.