Continuity mistake: When Drew sprays silly-string all over Kate, the strings differ in position between shots, especially when Kate says that she can hold a grudge.
Continuity mistake: While Drew and Kate stand on the corner in front of the billboard, as the people drive by and honk, Drew's briefcase falls off the bench onto the ground, but is back on the bench in the following shots.
Answer: "That Thing You Don't" (s03e10). The gang forms their old band again for a talent contest. Lewis is on drums, Drew is on trumpet, Oswald is on trombone, Kate is lead singer.
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