Babysitting today

So i'm going to be babysitting a three year old boy and an eight year old girl today along with my own eight year old sister. I already know the eight year old girl, so that's a good thing and i know she'll be easy, but ive never babysat her three year old brother! Or three year olds in general, just young school age children and one year old babies. What fun this will be. I think a trip to the park is in order lol. Anyone wanna throw some tips my way? My mom will be home too, as the mother is bringing them to my place, but my mom has errands and yardwork so i need to keep them out of her way. I have coloring books and blocks all set up in the playroom, and a toy box full of toys including a separate box full of cars and other toys we kept from my brother when he was younger, but aside from boardgames i dont really think we have much for a three year old...

Keep running,
~ Kari