After looking at this question, I began looking at votes/views ratio. I know that we can get some meta data out of the site, but are questions I would like to ask but haven't seen (from A51 for example).
One nice scatter plot to look at would be votes/views ratio, possibly as a 3D graph over time. I'm also thinking about trying to ask some good test questions in the highly specific field category and pop science category to see if we can watch these trends from starting at the same time. Of course I might have fouled things up by mentioning that here, so if I do, I'll at least wait a bit.