The first part of this video mention on several 3D printing technologies that are able to print with multicolours. The second part mentions two hacks/tricks which everyone with a 3D printer can use to make their own multicolour printing.
If you want to modify the code by yourself, here are the codes which you will be needed:
Beep sound:
M300 P20000 S660 ;
note M300 : beep sound command
note P20000 : beep duration (20000 ms) / (20 seconds)
note S660 : frequency 660 hz

Pause for filament swapping:
M600 E30.00 L300.00 ;
note M600 : pause for filament change command
note E30.00 : post retraction for (30 mm)
note L300.00 : final retraction for (300 mm) filament change