After the announcement in 2005 that Apple were going to change their Macintosh computers from the IBM/Motorola PowerPC range of processors to Intel's x86 line everyone thought they were nuts. Well it seems the insanity continues as Apple have just announced a program called Boot Camp that allows anyone with an Intel-based Mac to run Windows! Yowzers!
UPDATE: A 3rd party company has developed a $50 program called Parallels which lets your Intel Mac run a huge array of operating systems while you are still running OSX, i.e. no reboot required, thus giving you much more flexibility. While audio doesn't work and you can't access the CD/DVD drive, for standard applications I think this is a better way to go. Nifty.