The first album that popped into my head when I saw the thread title was:
The four songs on side one are really, really good, up there with the best stuff on NEU! and NEU! 75. But the second side of this album is incredibly frustrating to listen to. What I understand is that they had run out of money to finish the album and so they decided to fill the second half with tape experiments and remixes of existing songs. The results are less than impressive.