What do barbacks do in the time there nothing going on?

I start a job tonight as a barback.. i never did it before and i am a little nervous. i know what you do for the most part. Stock beer/liquor, get ice, clean glass, cut fruit, keep everything stocked. But what about when there isnt much going on? They said it wont be that busy tonight and i dont wanna stan around doing nothing. I want them to like me