With the first season of Lost nearing its end, it was about time the last of the main characters left on the list got his own episode - that would be Hurley (Jorge Garcia), whose role so far has been to provide comic relief (cracking jokes, building golf courses, the works). Like everyone else, though, he has his fair share of baggage, and this is the one where part of it is unveiled.
To be more specific, Hurley's past involves a series of numbers: 4, 8, 15, 16, 23 and 42. When he sees these numbers on a document Sayid got from Rousseau's camp, he sets out to find her, miraculously avoiding numerous traps in the jungle while Jack, Sayid and Charlie are left behind and go their separate ways. When he eventually meets the Frenchwoman, Hurley is told a story that has some sort of connection with his past.
Prior to getting on Oceanic 815, Hurley won the lottery, an event which subsequently caused his loved ones to experience bad luck. He had used the aforementioned numbers to win, and when he relates this to a mental patient who has a habit of repeating that same sequence, he is told "the numbers are bad". As he tries to find out the origin of the numbers, he comes to the conclusion that they are cursed.
This episode is a very good spin on a popular science fiction motif: the number 42 was of great significance to both Douglas Adams and Chris Carter, while J.J. Abrams himself had a thing for 47, which was linked to the more supernatural aspects of Alias. Here, it receives a more complex treatment, being weaved into the series mythology and playing an integral part in two characters' back-stories. In particular, Garcia gets to have a lot of fun with his role, mixing Hurley's natural charm with a hint of darkness and mystery (his connection to a mental hospital cries for a follow-up episode) and even poking fun at the reason he was cast in the show in the first place (Hurley is falsely accused of being a drug dealer, a part Garcia played in the fourth season of Curb Your Enthusiasm). So yes, for the most part it's all build-up, but there isn't a single dull moment in sight.