Help! Road trip with a 3 year old and 7 year old?

So I'm taking a 7-10 hour road trip with my two cousins. I have a 3 year old boy cousin and a 7 year old girl cousin. I know they look up to me and are going to be expecting me to entertain them. I have no idea! The 3 year old won't pay much attention very long so i'm stuck. I was thinking about teaching the 7 year old how to make freindship bracelets but do you think thats too hard? HELP!