Committed - Season 1 Episode 3 The Apartment Episode
Overview: Marni has never seen Nate's apartment, so she invites herself over one night. However, Nate is embarrased to have Marni see the clutter in his apartment, so he makes excuses to keep her away. Tess tells Marni to break in to see it while Nate is at work, only they get more than they bargained for when they do.