If you've been heading over here for casting call spoilers, this episode might ring more of a bell as "Dog Story". All I can think of is ABC must be juggling episode numbers/titles around. So we'll see come episode 14 if they're really one and the same - though the press release (official spoilers) does list Reid Ewing (Dylan) as a recurring for the episode, so we'll see.
Guest cast include Minnie Driver as Sue, Reid Ewing as Dylan, Brian Oerly as gym member, Blake Gibbons as construction worker and Andrew Harlander as creepy diner.
Oh, and Minnie Driver too. Enjoy these promotional photos for episode 14 of Modern Family, "Moon Landing" (to air Feb 3).
Source: TV OverMind