There is already a diary from Christian Dem in NC announcing the upcoming debate about creationism between Bill Nye and Ken Ham.
I think this is a bad move that will end badly, and I will give some reasons below.
1. A formal debate against someone legitimizes their position. The very structure of a debate pretends that there are two viable alternatives between which the audience can decide. For more on this problem see Tyler Francke on the God of Evolution: Theology with Attitude website.
What’s more, any modern-day public debate over the fundamental tenets of creationism is a sham, a mockery of real discourse. That’s because there is no scientific debate to be had over whether the earth is billions of years old, or whether life shows strong evidence of common descent, or whether a global flood occurred within the memory of modern man. These questions (particularly the first and third) were settled by the experts who are paid to study such matters long before any of the would-be “debaters” were even born.2. Ken Ham is a publicity hound, and this will give him and his Creation Museum publicity. For more on this problem, see the blog by Heman Mehta, The Friendly Athiest.
So, seriously, what’s the point? As long as we’re seeking to move the human race backward, shall we also take up the questions of “Is the earth flat?” and “Does thunder mean the sky is angry?” This is why the very act of debating a young-earther is a false pretext; it gives audiences the illusion that there is some valid controversy worthy of spirited argumentation, when, in reality, the participants are discussing a long-settled issue in which one side has simply refused to admit defeat (for reasons that have nothing to do with the evidence).
3. You can't win a debate against an opponent who does not have to play by the rules of evidence. When your opponent says "God made it that way," it's all over. More from Tyler Francke:
Even the evidence — as powerful as evidence can be — won’t save him, because evidence changes only the minds that are open to it. And those of Ham and his followers are not. They’re not looking for the truth, they just want their truth, and since they firmly believe they’re doing God’s work, they’re really not that interested in anything that contradicts it..
4. Supposedly the question for the debate is this: "Is creationism a viable model for origins?" This has two problems. First, there is no way Ham stays on this question. He will attack evolution. Second that is no way to prove in a debate that creationism is not viable, because it is. If you believe in an all-powerful God who can choose to make the world any way that God wants to, then creationism is viable. Any evidence that appears to the contrary is just part of the plan. e. g. If god created Adam and Eve as adults then God created the Earth with a mature appearance, including fossils in the ground. You can't argue against that, because it is not an argument itself. That's what makes it not science - it is not falsifiable.
Bill Nye will lose this "debate" because it is not a debate It is a spectacle, and Ken Ham is a master con-artist.
If I can add a fifth reason that came up in one of my comments below. If this debate comes off as "reasonable' by any definition, many creationists will ask why we can't debate the "issue" in the same way in public school science classrooms.