In all seriousness, here's how it works: Each Zelda game takes place in a timeline in the land of Hyrule, with OoT first and (as I recall) Zelda 2: The Adventure of Link last. OoT details the first conflict involving Link, Zelda, and Ganon; I believe there's mention of a prophecy in that game wherein a chosen hero and descendant of the Hylians (named Link) sort of cyclically defeats a recurring villain (Ganon) and saves the princess (Zelda).

So, the way I imagine it, there's a huge increase in parents naming their sons Link every time a princess named Zelda is born, so that their son can be the chosen one. (Though god knows why the royal family keeps naming their daughters "Zelda"...)

 @ pichu_pichu: The only Zeldas that are related are those in sequels to "main" games. So, the Zelda in both the NES Zeldas and Link's Awakening are the same, the Zeldas in OoT and Majora's Mask are the same, and the Zeldas in Wind Waker and Phantom Hourglass are the same, for example.

It wouldn't make sense for the OoT and TP Links to be the same, since Link would, you know, remember everything from his first outing of killing Ganon. :) 

im sure zelda is allways from the same family tree and link is allways from his familys family tree, and ganon is the same ganon who keeps coming back from the dead or from being locked up some place, now the big question is! WHICH LINK IN THE ONE IN SMASH!!!

So far none of the links I believe have been the same Link. Now I can't confirm that but yea.

They aren't descendants of any kind. IN stead it works like this. Each piece of the triforce is reincarnated into a different being each time the last one dies. So if you are reincarnated with the piece that Link holds then you are the next Link. About as simple as I can put it. Same thing happens with the Zeldas and Ganondorfs.

I think that every Link is sort of the same but they are all different. The only reasonable explanation is that every Zelda game has its own parallel universe. Like The One(Jet Li movie)

Everybody who said that each story is unrelated nintendo already announced a timeline , and this timeline is in fact a timeline that splits into 2 universes. Here is a video that tells about it.

Maybe the Hillian Royal family have the tradition of call all her daugthers Zelda xD

^^^ sc94597- that is simply a theory as Nintendo has never announced what the real timeline is. Not to mention that was made before Twilight Princess

o yes. Timeline in Zelda games... interesting thing :)

Legend of Zelda retrospective
if there is someone who haven't seen it, check out gametrailers.
http://www.gametrailers.com/retrospective.php

Nintendo did mention there was a timeline though even if it wasn't reveled. They also , said it was the split timeline , but nobody knows where each game goes.

Well, Shigeru Miyamoto has officially stated on several occasions that every Link is different. Well, almost. There are some that are the same, like the Link in OOT and MM, the one in TWW and PH, and the one in ALTTP and LA. Like someone said above, it's more like a retelling of the struggle between light and dark, but with different people. The only constant in the series is of course Ganondorf, in all his shapes and sizes. The Links and Zeldas are different people in different times in most of the games.
Please don't get me started on the overall Zelda timeline and chronological order, I'll be here all week. :p