Looking for unpublished problems

Hello.

For our next Nordest.pm meeting, we'd like to propose a Golf Challenge.
The competition will be open for Nordest.pm members until Jan 26, date 
of our meeting, during which we will announce the winner, who will give 
us a lighting talk or something to explain his solution. So far so good.

Of course, no member of Nordest.pm can submit a problem, since he would 
lose his right to partecipate. So I'm asking for an unpublished problem 
(middle level) which won't be used in other challenges until Jan 26. If 
you have something that you discarded for better of more difficult problems, 
it will be perfect.

Thanks in advance.

cheers,
Stefano