Chris Heilmann, over at wait-till-i.com is doing a workshop at the Paris Web Conference on unobtrusive JavaScript and covering his “Seven rules of Unobtrusive JavaScript”
- Do not make any assumptions
 - Find your hooks and relationships
 - Leave traversing to the experts
 - Understand browsers and users
 - Understand Events
 - Play well with others
 - Work for the next developer
 
Read more in his article here.