This happens during the middle of the movie, it is the first day that Terry goes to her new school. She is in the cafeteria and eating lunch by herself and across from her, the nerds are sitting by themselves at a table. Watch as Greg comes up to them and he lifts up their bench amd they all slide off the table bench. Look closely as they slide off and you can see the oil they put on the bench to make it easier for them to slide off.