When Sayid and Sawyer are fighting, Sayid says "Ibn al-kalb", which translates to "son of a bitch".
The comic book that Walt reads is Green Lantern/Flash: Faster Friends #1, published by DC Comics, and a polar bear really appears in it.
Broadcast restrictions prevented any shots of Charlie ingesting heroin. The producers got around this problem using clever cutting.
The case that flies out of the locker and hits Fredric Lehne's character on the head was made of rubber. Lane had tiny tubes hidden in his hairline, which then released blood to run down his face.
The plane crash sequence was Evangeline Lilly's first day of shooting on the show. Because she is Canadian, a special U.S. employment visa had to be arranged for her. Since this took such a long time, all scenes that featured her character had to be pushed to the end of the shooting schedule. When the visa finally came in, she was flown to the set the very same day.