गूफ़

Sheldon orders Raj and Howard to take him to buy a gift. While he's out Leonard returns home after dropping the motorcycle on himself.

When Leonard hits the door with his head and Sheldon opens it Sheldon is wearing a completely different outfit.

Sheldon is then shown to be in the bath item store wearing his original outfit and returns home to find Leonard on the sofa.

Penny brings her gifts for Leonard and Sheldon to their apartment before Leonard drops Dave's motorcycle on his leg. When Leonard and Penny open their gifts to each other, it appears that the motorcycle lessons are Penny's only gift for Leonard, but he hadn't hurt himself when she bought the gift.

In the beginning of the episode, Dave Underhill entered the cafeteria scene and sat with a group of people. During the scene, he changes seat 3 times within a 15 second span.

Just before Sheldon begins to explain Saturnalia to Penny, and just after, Raj is shown sitting in Sheldon's spot. No one says anything.