I know you'll all hate this answer but... RBN.
And as far as this week's DLC...thanks for saving me some money, HMX.
Kaipa, man, Kaipa! Ten minutes of proggy excellence :D Seriously dude, if you like prog, get that song. It's a good one.
Kaipa formed in the 70s according to Wikipedia.
inb4 70s isn't Classic
EDIT: The band is from the 70s, but not the song. Whatevs.
Congratulations to 311 for making it to Rock Band.
Indeed, RBN has been strong for prog this year. Cynic's "Evolutionary Sleeper" and Kaipa's "In the Wake of Evolution" are among my favorite tracks purchased this year, RBN or otherwise. I've also bought a track by Mystakin (which is aptly named, oops), and I will probably get some more Rishloo if the HMX DLC stream remains dry.
This is possibly my favorite pack since Black Keys 02! Total buy for me!