The Mozart Effect
I wonder if playing classical music - particularly Mozart's Sonata for Two Pianos in D Major K. 448 - has a beneficial effect? This Wikipedia article says that some research has been done into the effect and has indicated some improvement in spatial temporal reasoning.
It does go on to give a balanced view with headings such as The Limitations of the effect.
Well, even if it has no mathematical effect, it would be nice to listen to music in the classroom during individual and smaller group work time.