I've updated the FAQ to explicitly specify some categories that we do not cover, but I'd like to also include some verbiage on what types of games we do cover.
Making this Community Wiki, please feel free to edit the main answer or supply your own as you desire.
2011/01/17 - The main faq section "What kinds of Questions should I not ask here?" has been updated. This update came from the StackExchange team and applies to all SE sites.
I also added the blurb from the comment below.