Dave Shea, of mezzoblue has an very good posting on MOSe. This has been in discussion before, with Steve Champeon, Mike Pick, CodeBitch, Web-graphics, Simon Wilson and so on.
MOSe (Mozilla/Opera/Safari Enhancement) relies on IE6's inability to pick up child and adjacent selectors within CSS.
He has created an example of at Zen Garden called mnemonic. So go take that apart and see. But the whole thought process is somewhat similiar to the NN4 process that was developed to provide CSS support. Provide a functioning page, and then enhance it with CSS.
Now, I am certainly NOT advocating that we screw IE. I think that the page should be developed first and foremost for the marketshare leader of browers. But I also find this movement of enhancement for capable browsers interesting.