The Windows install and upgrade process isn't normally something users get nostalgic over - in fact, more often it's an anxiety-provoking experience that most would rather avoid - but for one man it's an opportunity to track Microsoft's OS progress over the past 25 years. Andrew Tait started out with a copy of MS-DOS 5.0, installed Windows 1.0, and thus began a 10 minute video showing (almost) every upgrade to the platform up to Windows 7.
We say "almost" because Windows ME is missing; users were only able to upgrade to ME or Windows 2000. We're betting most people wish that ME was absent from the timeline too - the Millenium Edition was little-loved and quickly replaced by Windows XP.
Tait used VMWare to install each stage of the Windows timeline, and tested each version with Monkey Island and Doom 2. We're sure the Mac OS X version of this will be along any day now.