So I tried my semi-tongue-in-cheek neurobic exercise: I played Guitar Hero left-handed last night. I got through the easiest song (Slow Ride) on the easiest setting, but stank up the joint in a systematic, predictable way, making the same errors over and over.
Then I tried playing an unfamiliar song on medium with the volume turned off completely. (But right-handed.) Interesting but takes the fun out of the game.
Not sure I feel any smarter.