Well, apparently now you can. As if having the option to run Windows on your MacBook wasn’t enough already, you can now try out that stripped down operating system that’s kicking around inside the OLPCs that they’re shipping to third world countries. Basically, you achieve this through “the magic of VMWare and Parallels” (as Gizmodo put it).
The entire process takes place in three steps. There’s a pre-configured image that you’ll need to download, a few settings that you’re going to need to change, and then there’s the stumbling, bumbling, and fumbling that you’re going to need to do to figure out how this OS actually works.
Mac OS X looks awfully pretty and Windows Vista is quite a looker itself, so why would you want to even consider a downgrade like this? Well, out of the goodness of your heart, you could develop some software for the OS so that the kids in Nigeria can actually play Doom. And yes, that has already been done.