Episode #1.8 - S1-E8
Continuity mistake: Towards the end, as everyone's gathering outside, Ken Marino has his hand in the front pocket of his shorts. The shot switches to a view from behind, and it's in his back pocket. Back to the front, and it's back where it was before. (00:22:10)
The Elephant in the Room - S1-E2
Continuity mistake: When Phil storms out during dinner and comes back in, he closes the door (we even hear it latch). When he proposes to Carol, the door remains closed until after she says yes, then in one shot it is open and stays open, with no one touching it.