I just send this email to NASA:
I was wondering, besides your missions concerning the advance of science, health and technology, why not do some art too?
It would be cheap and easy: you would just give some white sheets of paper to the next astronauts on ISS and some water soluble, non toxic paints (a small amount would do), and let them do some watercolors in orbit. I imagine they could put some drops of diferent colors and sizes floating and then "catch" them in the sheet of paper, with diferent angles and diferent speed. Or any other process they would invent, taking advantage of the lack of gravity. That would make a good hobby for the astronauts, they could film it, and, back on planet Earth, make an exhibition and sell the watercolors.