Let me preface this post by pointing out that many works placed under the tag of "minimalist" doesn't really sound all that minimal. The tag really refers to the techniques of repetition and sustained notes and less to how much is going on to your ears. In that sense, "minimalism" is a misused label that probably pushed away potential fans of the music. Having said that, I'll begin my guide with the first "minimalist".
Ok, this piece actually is legitimately minimal. This isn't La Monte Young's best piece (see "A Well Tuned Piano") but it sure is indicative of what he is all about. Essentially, he listened to some classical indian music and decided to take the drone noises in it to the extreme in a classical music context. He could be called the father of drone music and by extension, ambient music.
This is interesting because it's meant for up to 35 musicians and the artists in each particular rendition have the ability to play a part and stop playing it at their own discretion. This gives each version of it generative element. It also gave the inspiration for the next 2 seminal works I am about to post.
How this is considered minimal I have no clue, but it demonstrates the common minimalist theme: shifting parts, repetitive motifs. A seminal classic.
Similar to the above work, this one is a little bit different in that it's even more complex and is based around two repetitive loops that move in and out of sync aka "phasing". This gives it a really hypnotic element.
This one combines the repetitive complex styles of Glass and Reich with the stonings of La Monte Young and makes for quite the completing and hypnotic piece.
Tony Conrad is a La Monte Young protege who also specialized in drone. This is a pretty good one in particular because Faust (a Krautrock band) also contributed to the piece. It keeps with the traditions of the style regardless.
I couldn't resist including this. It's long and complex but if you liked any of this other stuff you'll be very rewarded by it.
And this concludes my guide to admittedly less than minimal minimal music.