When I was about 9 years old, I downloaded a key-gen for Sony Vegas 9. It wasn't the newest version, but I made do with what I could get my hands on. When I booted up the program, I was greeted to this incredible piece of music that changed my life forever.
What I didn't know at the time, was that this program was made in a format called "XM", a music format based around playing samples back with hex values, rather than one single long waveform (think of super nintendo vs mp3 or wav). There are actually a few formats like this, including MOD, IT, and S3M. All of these formats are essentially based around loading samples and playing them individually rather than condensing everything into a waveform. There are differences between all of these of course, but they all have that key principle of sample-based playback in common.