When my kids were younger, they were each assigned the task of coming to the seder with one or two thoughts or facts they wanted to share about the seder. When they got a little older, they had to come with one or two questions they wanted to ask. They did not need to know the answers to the questions. The whole point was to make them think about Pesach and the seder and to incorporate what they were learning in school with their own curiosity. As they got older still, I needed to become more creative to keep their interest in preparing something. Last year, for example, they had to find a song that pertained to some aspect of the seder and then sing that song at the appropriate point in the seder, and then explain the relevance of the song to what we were doing at the time.