In the Episode "Promicide" Season 4, the gang are at their Prom on a boat. 'Jen' visibly cold, is getting drunk and jumps up to sit at the bow of the boat whilst talking to Drew. As she pulls herself up, her foot pops into the lower corner of the screen and reveals: a sheep-skin slipper! Not exactly something you'd wear to your prom! Obviously these were not meant to appear and were worn to keep the actress warm during the scene.