Translated as unleavened bread, matzah is actually more of a flat cracker. Unlike what you may have heard, they are not made from the blood of Christian babies. (blood libel) But there are specific regulations as to how to make them, which is why not even a Martha Stewart of Jewish mothers bakes her own. Instead we buy them at the grocery store from companies like Manischewitz. According to the narrative, the fleeing Jews were given such short notice when they were allowed to leave Egypt that they didn't have time to wait for their bread to rise, baking quick flat bread on the desert rocks instead. For the eight day festival (not just the seder), one is supposed to refrain from eating any chometz and eat matzah instead. Besides making good matzoh ball soup, it's also used to entertain children who get very bored by large family gatherings that involve talking at length about religion. Towards the end of the meal, as the adults ramble on, the kids search for the afikomen, or middle matzah. Finding it usually results in the winning of big prizes or just chocolate.