The major labels have finally figured out that while extremely uneven homemade tapes sound like crap as demos, they can come off as pure eccentric brilliance when released commercially. So goes the story of Daniel Johnston: two-track loser in Slackertown U.S.A. (Austin, Texas) since 1980, when he began releasing a continuous stream of songs on cassette via his own Stress Records and small indies like Shimmy Disc. All the while he cultivated a small but important following that included a Cobain and a Vedder, plus friends like Mo Tucker and Jad Fair. Now, just in time for his first major-label release, Johnston is a certified underground legend. Admittedly, Fun is not a very major-sounding major-label record. It runs low on overdubs and slick production, with accompaniment that at times consists of only one instrument--a cello, a tinny guitar, a cheap keyboard plunked at random--or nothing at all. On children´s songs like "Happy Time," Johnston sounds like Ween doing Jon