Continuity mistake: As Charlie Brown, Patty, and Marcie are talking, the grandfather clock strikes four. Trouble is the pendulum is stuck in place, first on one side, then the other. It doesn't swing.
Continuity mistake: When Linus and Lucy are talking to Snoopy he's got a shopping cart stuck on his right leg. Then, when he's getting on the bus it's suddenly on his left leg.