Small IR box connected to the 30-pin connector then code to replicate a Wii Remote. Not sure if you can spoof the Bluetooth Ids so the Wii will connect. Obviously not that useful for gaming but maybe for reverse engineering, macros, keyboard?
Microsoft has been rewriting many apps in.NET Office 2007, (most of) VS2008, (all of) VS2010, Windows Media Center, and probably many others. I'd guess the small apps like the games and calc. Of course the kernel will never be and I'll bet even some of the above apps link to native code but I wonder if MS is positioning itself to be able to move to other architectures more easily.