We've actually discussed adding a game forum, but really, we don't see enough real gaming questions to make it worthwhile. You're welcome to ask your gaming questions in the J2ME or Java in General forums, as appropriate.
The problem I see with a single "Java Gaming Forum" is the broadness of the term "gaming" and the technologies aside from Java specifics that it can entale. Java.net already has a pretty good Java Gaming Community as well as Discussion Forums.