Example: Dark
1. Comfort the computer users. When the power goes out, the first people to notice are the computer labs, mostly because shit just got real for them. Thy will not be able to comprehend that facebook is not run by magical fairies, but instead by papa power and papa got drunk and passed out. These patrons will panic, blindly accusing you of causing their virtual crops to wither and their friends and families to think them dead because they could not post "powers out at the library lol @ashtonkutner" to their twitter feeds. Hold them and tell them to be patient, cry with them and let them know that everything is going to be all right. Keep them from attempting to attatch their car to the library in the hopes that they can give the library a jump.
Remember, it's black to ground and red to library.
2. Call the power company. This seems like a no brainer, but often the company that supplies that high voltage life blood will not know they have screwed up. Let them know, with a kind and forceful tone of "we are about to be murdered. Send help." That will get them running. This is especially important because the patrons will get restless and rioting/looting will ensue.
Holy Crap?! The power was only out for five minutes!
3. Bust out the flashlights. Use the flashlights to scour the library for all those teenagers who find their lust sparked by darkness or their appetite for stealing amped up (see what I did there, with the electrical talk? amped...). If you do not have a flashlight handy, grab a blind person. They already know how to get around in the dark. Then, guide any well meaning crotchety old person away from squinting at the large print. Gather everyone into the biggest open space you can and begin dividing up into teams of "kill" or "be killed."
Example: Kill
4. Kick everyone out. Move those flashlights toward the entrances and those patrons will flock to them like ferrets (true story). Any who resist the first push will be trampled or given a stern talking to. After the majority of the people have fled into the bright, shiny world, the librarian must go back in to get the rest. Who would stay in a creepy, dark building filled with frightening angles? Weirdos and freaks, that is who. Be prepared for anything, and I mean anything.
Like Johnny Applescreamer
5. Prepare to reopen. Many of you know, reopening is nothing like opening. An unscheduled closing and reopening during the middle of the day causes imbalances in people with already little in the way of "balance," much like introducing a shark "imbalances" a beach. Apologies will not cut it this time, buster. You will have to reign in the crazy that is "patron." Preparation to reopen rests on two principles: turn everything on first and prepare for stupid.
What do you mean it didn't save when everything cut off?!