Sonny with a Chance: "Tales from the Prop House"
Directed by Eric Dean Seaton, U.S.
Aired August 2, 2009 (Season 1, Episode 15)
The kids are apparently in danger of losing their prop house, according to attorney Maurice Levy - sorry, Marshall Pike - played by Michael Kostroff.
Their photobooth is apparently home to a rat, who comes back in the end to freak out the new occupant and let the prop house return to its old occupants.
Thanks to Aimee for the tip.
Contributed by Brian