I recently convinced an author of Atari 8-bit (800, 800XL, 130XE, etc.) software to release the source to some of the programs he wrote. It can be found at http://nleaudio.com/css/source.htm.
I also recently disassembled the SCSI-related portions of the Macintosh IIfx ROM. It can be found at http://sdi.cluephone.com/~jason/fxscsidump.S.
If you're interested in looking behind the curtain of web advertising (Slashdot advertising in particular), check this out.