This should be very easy to implement... I think there should be an option for listing questions by oldest. There is, of course, the 'newest' listing option. Why not just make an 'oldest' beside it? Or click a second time on newest and it switches to oldest? I think another method might be letting someone input a date range.
The problem is getting to the old, unanswered questions easily. As it is right now, it is difficult to get to most of the questions without taking random stabs in the dark with tabs or clicking through page after page. I think Random sort for Unanswered questions is a step in the right direction as well.