Topsy Turvy - S1-E10
Continuity mistake: When we see Alfred in the Batcave, he had 4 neat piles of playing cards and turns over an Ace. When Batman arrives, there's a shot of the cards, but the Ace is no longer turned over. When he makes the comment about seeing another playing card, the shot changes and there's now 5 piles but not in a neat pile.