Kyon, your typical high school student, has long given up his belief in the supernatural. However, upon meeting Haruhi Suzumiya, he quickly finds out that it is the supernatural that she is interested in—aliens, time travelers, and espers among other things. When Haruhi laments about the lack of intriguing clubs around school, Kyon inspires Haruhi to form her own club. As a result, the SOS Brigade is formed, a club which specializes in all that is the supernatural.
Much to his chagrin, Kyon, along with the silent bookworm, Yuki Nagato, the shy and timid Mikuru Asahina, and the perpetually smiling Itsuki Koizumi, are recruited as members. The story follows the crazy adventures that these four endure under their whimsical leader, Haruhi. The story is based on the light novels by Nagaru Tanigawa.
The episodes for this series were intentionally not broadcast in chronological order. Hence why at the end of episodes, the next announced episode number did not always match. Usually, Haruhi would announce it only to be corrected by Kyon. This leaves two different options of viewing: chronological order or broadcast order.
The chronological order of episodes is: 2, 3, 5, 10, 13, 14, 4, 7, 6, 8, 1, 12, 11, 9.
Please see: http://en.wikipedia.org/wiki/List_of_The_Melancholy_of_Haruhi_Suzumiya_episodes
for more info
Summary taken from: MyAnimeList