A rationality without dancing is not a rationality worth having. If there won't be dancing at the rationality, I'm not coming.
Here are some answers to your question:
Less Wrong Q&A with Eliezer Yudkowsky: Video Answers
Eliezer Yudkowsky explicitly mentions art in the first video.
I'm reminded of the lawyer in the unit of caring post. They could contribute directly in time or money, but it's a more efficient use of their time to do what they already specialize in and then using that specialty for the cause (either by contributing the earnings of that specialty or be doing the work directly for the cause). By the same token, it seems like if you are already inclined towards or talented in art, it doesn't make sense to, say, drop it and become a programmer just because it might help towards the singularity. Take the thing you do and find a way to make it work for the goals you want to support.
Go ask Pete Seeger.
Although in these days it seems that the most common form of persuasive art is the film documentary.
it also seems as though one big success (say, a musician whose music was primarily about the singularity and increasing rationality) would turn many people on to the ideas.
I think that's the point of Harry Potter and the Methods of Rationality.
What are your thoughts on the role of Art in rationality (personal or otherwise) and in the singularity?
If one wants to help in the efforts of SIAI (or other organizations) does it make sense to focus on an art form as more than a hobby?
Is it rational to pursue an art form that encourages people to contribute to a cause when there are more direct ways of contributing?
It seems difficult to receive much recognition for one's work in art related fields, but it also seems as though one big success (say, a musician whose music was primarily about the singularity and increasing rationality) would turn many people on to the ideas.