There's been a lot of mention of the unreleased Dreamcast port of Half-Life, but no mention of the Mac port. Many old school Mac users may remember that a PPC port of HL1 for OS9 reached golden master but never got released (or even leaked, to my knowledge). Valve just quietly released an Intel Mac OS X port of HL1 earlier this this year to little fanfare, marking the first time the game has been available for Mac; over a decade after the original port.