12-hour babysitting adventure recap!

Thanks to all the awesome GTers who provided excellent advice for my babysitting adventure. The kids LOVED Shiny's baking soda treasure rocks aka "magic dinosaur eggs". We spent a lot of time dancing and watching old Mickey Mouse and Silly Symphony cartoons, and we went swimming, had craft time and then pizza for lunch AND dinner (as per instructions from parents). There was only one mini-meltdown related to a skipped nap and the perils of toothbrushing, and a four year old's desperate efforts to avoid bedtime. Miles the wonderdog (who is exhausted today) was a DREAM with these children, playing hilarious lifeguard around the pool and was content to snuggle belly-up when the kids wanted to watch TV.

All in all, a great success! I appreciate everyone's suggestions!

GT Minders of Toddlers/Kindergartenders

Please help! I will be babysitting my friends' 2 year old daughter and 4 year old son for like 12 hours on Sunday (if I do it right, they will be asleep for approximately 3 of those hours). I do not have any children but I love these kids and want to be a cool fun babysitter with age-appropriate activities. What should we do?! How long will it keep them entertained?

The 4 year old is totally obsessed with dinosaurs and music, and the 2 year old will (I believe) do whatever her older brother does. I want to do some baking or maybe some crafts but both of those things scream messy...

I will also have Miles with me as a baby-sitting sidekick.

I know that as a fall-back I can always watch a movie with them to kill some time, and they have a pool so we can get some swimming in too; but I don't want to rely exclusively on those things because 12 hours is a long time. Any and all advice is much appreciated!