Why the plagues?

My Bible study group recently went through the plague story in Exodus. One theme that kept surfacing was that of attitude toward miracles: the miracles of the plagues are presented as dramatic evidence of God's will. And yet in modern Judaism, as explained by the midrash The Snake Oven, miracles are rejected as evidence of God's will.

In Deuteronomy 30, where Moses is explaining the importance of following God's laws, verse 12 states that a record of these laws "is not found in heaven." The Jewish understanding is that God gave Torah on Mount Sinai, and the post-Sinai interpretation has been entrusted to Jewish scholars: God has agreed to stay out of it.

The Exodus story is so important in Judaism that it has a major holiday devoted to it: Passover. Our study group found the prominence of the plagues in this story to be a stark contrast to the religion's current anti-miracle stance.

The first time this question came up, our rabbi pointed out that the Passover holiday emphasizes the "journey to freedom" aspect of the story, and the plagues get only a minor mention. This consideration lessens the seeming contradiction, but doesn't eliminate it entirely.

Later, we discussed a more interesting possible explanation: in Exodus 10:2, God explains that he causes the plagues so that (as translated by the Jewish Publication Society) the Jewish people will recount the story "in the hearing of your sons and of your sons' sons... in order that you may know that I am the Lord."

At Passover, the Exodus story is recounted in the presence of children. This practice is widespread even among otherwise non-observant Jews: Passover is the most widely celebrated Jewish holiday. The dramatic story of the plagues has motivated generation after generation of parents to tell their children about God's power. If that was their purpose, then the plagues have been wildly successful.