Violin
It is a pity for a person like me without any expertise except my own major(CS) over 30 years old. Now the opportunity comes: my kid is attending a training violin class. At first the class is so boring, fundamental practice, music theory.... Until recently, Violin attracted me deeply. Following the guru of violin, watch the video like the Itzhak Perlman, yes, it is pretty interesting.
My kid and I are deliberately practicing in each sparing time. We are really enjoying violin nowadays. Violin is the most achievement in 2013, thanks Violin!