Currently on the main philosophy page there is a question, Are there universally agreed masterpieces of art?
The opening sentence of the question sums up the issue: "What do you consider examples of great art?"
This is the clearest case of an "opinion-based question" I have seen, putting it in a category which is normally closed without ceremony. However, the author also explains why he is asking a question of this form. He is seeking to collect information to arrive at a statistically valid position.
I believe this is also a forbidden form of question, as the forum is not designed for the collection of live philosophy data. However, he worded the post so clearly and it's such a poignant question that I really want to help, rather than voting to close the question.
Can anyone think of a good approach to keeping this question open without violating any written or unwritten standards we hold ourselves do? As an example, I'd consider a discussion where people provide their own opinion (voting style... also a questionable use of the forum), and then he writes his own answer and accepts it, summarizing his results. That way the forum continues to contain useful information (in this case, on what art is). Hopefully the value of that information would offset the amount of rules-bending it took to arrive at it.