Have an existential crisis at how thoroughly unfulfilled uninteresting and incomplete you are as a person to not know what to do with yourself during brief respites from going to your dead ass job every day.
Maybe you'll come to terms with the fact that you need to radically alter your lifestyle soon before it's too late, assuming it isn't already
Or sit at home on the internet in your big empty house eating unhealthy food for most of the rest of the leisure time in your short, short, very short life that will be over so soon.