Pesah - Haggada
The night we read the haggada and have the mitzva of והגדת לבנך - relating the story of the exodus to your children - is called the Seder. The Seder Night. We ask, "Where are you going to be for the Seder?" or "what did you make for the Seder meal?"
Seder means "order". The night and process should be called the haggada - the telling over. Why "seder - order"?
In addition to the night and meal being called the "seder", we also break the haggada into sections and at the beginning of the haggada we announce and chant the names of all the sections, as well as during the seder itself we announce whenever we have arrived at the next section.
One does not just embark on a journey. One has to first plan the details. You select the proper route, the equipment you need to pack, the various items you might need to bring with. If you just got up one day and left on a journey with no planning, you would be unlikely to finish it successfully.
The same is true with Judaism and the Torah. If you just hit the road one day with no plan of where you are going and how you will get there, you would be unlikely to navigate the paths successfully. You have to have a detailed plan to follow.
The "Seder" is the itinerary for the journey through the retelling of the exodus, and subsequently for the transmission of our history and tradition to the next generation. Before we embark on the journey we have to read through the itinerary so we know where we are going, and then along the way we stop at the various rest stops and recheck the itinerary at each step. We have to constantly recheck so as to be sure we are still going along the right path. Any deviance would make the whole journey unsuccessful, so we constantly have to make sure we are headed the right way.