Lemmy has got me feeling in a mood, so I'm gonna get crazy & try to be socially functional for once instead of just lurking & leaving. There don't seem to be many communities for prog, so let's get this going.
Right off the bat, I'd like to mention
The Desaturating Seven
by Primus. I don't even know what to say about it, it's a journey.
The entirety of Language - The Contortionist is what I consider a prog metal masterpiece, but specifically The Parable is so good that I have played it for people that don't like any "rock" genre and it wowed them.