Up until now, the only way to 'see' music was either by taking a lot of acid, or turning on the Windows Media Player visualisation setting. Neither are advisable for your health.
However, Mexican design studio Realität has used some nifty software and a 3D printer to create an entirely safe method of making music physical, in order to produce what they term 'Microsonic Landscapes'. They've taken the audio waveforms of five records, utlised the data using the Processing software and then realised them using a plastic 3D printer called a MakerBot.
As you can see, different records have different physical textures and shapes: Nick Drake's acoustic-based Pink Moon has a fairly even 'topography', whilst Portishead's Third has some big peaks and troughs.
See below for three examples, including a spectacular close up of the detail. More images can be found here.