The Internet Underground Music Archive was most heavily active back in the '90s, before being sold out as part of the dot-com boom and eventually fading away back in 2006. Enterprising souls have unearthed dusty archive tapes and resurrected the archive for your listening pleasure. Not that the archive is a repository of the finest mainstream '90s music; this was an "underground" archive, after all. Still, what's been revived is still a hefty lot, even if some of the file formats are likewise very dated. Still, you always wanted hundreds of hours of MP2 format music, right?
As a side note, this almost perfectly illustrates the point I was making earlier in the week about the perils of digital data; the IUMA only went offline in 2006, but what's been revived is but a fraction of what used to be there. That was only six years ago, but countless bits (pun not intended) are effectively now lost forever. [UIMA via Wired]