Half-Baked - S2-E2
Continuity mistake: When Haley is sitting on the couch she has a small piece of cupcake left, but as her father picks her up and puts her on his shoulders, she now has a whole cupcake missing just one bite. (00:12:30)
Continuity mistake: When Katara is trying to heal the wounded earthbender, she gives Sokka the idea to take down The Drill from the inside. Sokka then stops her from saying anything while she is sitting down, and she is wearing her necklace. When she stands up in that same shot, the necklace is gone, like they forgot to animate it. (00:07:35)