Acceleration data outputted from an acceleration sensor provided in an
input device is acquired and a magnitude of an acceleration is
calculated. Next, based on the calculated magnitude of the acceleration,
at least one piece of track data representing a target music to play is
selected from music piece data including a plurality of pieces of track
data stored in memory means. Then, based on the selected track data, data
for controlling a sound generated from a sound generation device is
outputted.