I know, this is a really REALLY broad.
What kind of interesting question lists can you generate from the data dump (that you can not get by using the SO UI)
Here is one I prepared earlier.
List of all the unanswered questions by people with more than 5000 rep. (note I can not exclude closed questions as the info is missing from the dump) Also some of the list is out of date.
The list goes on but I have no clean way of displaying it here.
This might result in interesting filters to display questions on the frontpage: only show me posts from users with rep +5k related to C
Though that would require some change of the SO UI... and is not really answering your question either...