This line caught my eye:
Obama pulled out five $20 bills to pay for the two books.
This made me wonder: how does the president get cash? Does the White House have an ATM? Does he call up Tim Geithner and have him send some over? Does he call Ben Bernanke and have him bring some by the next time he's in the neighborhood? Does the Secret Service get it for him? How? Do they go to the bank for him? Wouldn't that mean he would have to give them his ATM card and his PIN?
Just couldn't stop thinking about that.