First, you drop them off at Grandma's on your way to Mexico...oh, maybe not. I'm a third of the way through summer with my preschoolers and I'm pretty sure the only thing that's keeping them alive is how impossibly cute they are. It's certainly not my patience and skills or their exemplary behavior that's allowing us all to survive.
Canadian nonprofit organization Invest In Kids has, for your consideration, a little guide called "Comfort, Play & Teach", downloadable as a PDF and brimming with all kinds of useful information to help ensure your child will live to see September. Activities for just about every area of interest, from quiet to full-on-party, from things your kids can do at the coffee table while you're checking your email to things the whole family can pile into the Prius and head out to experience. And because Canada rules, the guide is free.