Continuity mistake: When Nora dies, Lynette stands up and strokes her hand over her chin, so a little blood stays on her chin. During the yelling scene of Lynette towards Carolyn, the blood on her chin changes constantly between shots.
Continuity mistake: In the scene where Carolyn shoots Lynette, Lynette is wearing high heels when she is originally shot. But when Lynette falls into Art's arms, she is wearing shoes without heels.
Chosen answer: Poker. They have been playing that this whole time, once a week with everyone who was invited that lived on the Lane.