This site (http://programmingpraxis.com) publishes every week very interesting code challenges, that could totally fit here.
Example: http://programmingpraxis.com/2014/07/25/number-words/ : that would be a perfect code-golf question.
Do you think we could, or should automatically publish those challenge here?
I emailed the webmaster to ask his approval
EDIT: here's the answer of the author:
I wouldn't want to post complete exercises on codegolf.stackexchange.com; I'm happy to keep my blog for that purpose.
If you wish, you are welcome to post pointers to my exercises. Perhaps a short description of the problem, followed by a link back to my page. Many of the exercises are simply too long for a Stack Exchange posting, and the two-page exercise/solution format doesn't really fit.
Are you sure my exercises fit your code-golf topic? Some of them do, for instance the recent number-words exercise, but some of them would make a bad fit; for instance, no one is interested in a code-golfed version of elliptic-curve factorization.
So we can are allowed to use the puzzles that are suitable to code-golfing under those conditions. That's great. Do you guys agree with those conditions?