Do not play at the park on the first Friday of the month at noon. While this sounds just fine, it is not good when you don't realize that a tornado siren is right next to all the toys.
On a side note, if you're looking for a way to have 40+ children stop dead in their tracks (and then have 20+ parents scrambling to cover ears), I now know just what to do.
My ears still hurt. An extra set of hands would have been nice so I could cover my ears and not just Micah's.