Taking Safety Measures
With any luck, you won't actually have to deal with illness or injury, but you know the old adage.
Get critical info
Obtain cell and home phone numbers for every parent. Inquire about guests' potential food allergies or other health issues. And, for goodness' sake, get clear directions on how to use a guest's EpiPen—an epinephrine injector to treat an allergic reaction—before her parents leave, so you don't accidentally inject your own thumb. Happens all the time—Google it, or just ask my husband about his very embarrassing visit to the ER with a completely white, swollen digit!
Check in regularly
Under the guise of "bringing more snacks," pop in every hour or so to be sure that 1) all guests are indeed still present and 2) everyone is generally getting along.
Light their way
Strategically place nightlights in the bathrooms, near the stairs, and in other key spots. Even older kids get disoriented in the dark.
Set a bedtime
Pretend you expect them to sleep, so you can at least get guests calmed down by turning lights low and putting on a quiet movie. Of course they'll protest, but some party-goers will be secretly relieved they don't have to "pull an all-nighter" to seem cool. Some older kids may never completely sack out—they'll fake sleep until you go to bed and then get up again—so resign yourself to the fact that you'll be coming back throughout the night to settle them down.
Show them how to find you
Every child should know the route to your bedroom, in case of emergency. Reassure everyone they can wake you if they are scared, sick or otherwise need some assistance.