babysitting for a 9 year old girl and 11 year old boy?

I am going to be babysitting regularly for a 9 year old girl and 11 year old boy during most of the day (morning until late afternoon). I've watched them before but the last time was a couple years ago, so of course some of what we used to do won't work anymore. They are very active so I would like to have some ideas in my head, just in case... novelty would work (at least the first time!)