nordlead on 14 September 2009
Strictly in the winter (Dec, Jan, Feb), there is nothing known, not even Spirit Tracks 
However, if you want to go from Nov-March you get Spirit Tracks. If you want to venture into April there is a chance that they release Pokemon Heart Gold/Soul Silver and possibly Glory of Heracles
Luckily, there are a lot of good games from 3rd parties coming out though.
