I think it really depends, because keep in mind, no matter where you are, it's always going to be someone's middle of the night, or first thing in the morning, or bedtime, or whatever. So, there's always going to be someone up and answering between loads of laundry, or up because they can't sleep, or whatever :-)
For example, it's almost 3 pm on Saturday here, but I know that it's almost 11 pm on Friday at my inlaws. So, I'm up and being a bum on a Saturday afternoon, but my sil could be up and on here before she heads off to bed, so....
at 1:49 AM on Sep. 18, 2010