Last year, I posted some goofy songs to add to your seder. The songs belong in the all-important "Maggid" section of the Haggadah, which is often unclear to children.
Here's the link: http://klempnerkids.blogspot.com/2010_05_09_archive.html
I'm in the process writing a new song, for when the Jews reach the Yam Suf (Sea of Reeds). Will post by the end of the week, IY"H.