I went so far as to read to them, creation stories from Hindu, Native American, and Judeao-Christian traditions. I followed up by having them choose one of six positions on the subject of teaching creationism, and then having them write letters to the editor supporting the position they had chosen. The point of the whole discussion was that maybe creationism has a place in social studies, but it has no place in science. At no time did I spend any time trying to debunk creationism's arguments. It worked pretty well, and it helped to defuse some of the closed-mindedness I was getting from some of the children who were from fundamentalist homes.
Just my two cents worth.