"A friend of mine spotted a 'Coming soon — In & Out Burger' sign in Union Square this morning," a Grub Street tipster wrote us today. "Could be hearsay," he warned. We're wary; it is April Fools' Day, after all. But could we at least dream a little? Because a different reader wrote us on Monday — four days before the Fool — to tell us she heard In-N-Out was coming, too. (We'll give a call when their office opens.) This is New York: Anything is possible.