I think of it as a public service: you're working on your Operating Systems assignment at 1am and discover your AC adapter has malfunctioned and you have 5% of battery left.

24/7 Apple Store. They're doing god's work.

You borrow one if the 5 million other AC adapters on your dorm floor...

Special thanks to the new MagSafe - this is no longer possible (short term anyway).

I was under the impression that pretty much all of the major US cities were 24/7 economies, with store times matching up.

Here's a tidbit that might entertain, then: in densely populated suburbs, you're less likely to find what you need at 3am than in small-town America (at least, in the rural South). That's because Walmart is typically open 24 hours, and Walmart in rural areas has essentially everything that's not very specialized.

Upon moving from such a place to the suburbs of DC, I was dismayed to find that finding a store open at 3am was actually more difficult than in the hinterlands.

No doubt. When I moved to Minneapolis, MN from ND, I was constantly amazed at how little is open in the early AM. Heck, even the fast food places closed early[1]. ND small town is more 24hr than the cities.

1) and what unholy foolishness of closing offsale at 8pm on weekdays, 9pm Fri and Sat, and closed all day Sun. WTF? "Backwards" ND has Sunday offsale.

Not really. I think NYC is the main city that doesn't sleep. Other large cities I've been to like Seattle get pretty dead late at night. The town I go to school in, Providence, even has a 2am business curfew.