Bored ? got a spare decent system lying about ? Well give this a whirl.. Windows Server 2008 beta.. Dont install it on the system you are using but give it ago on another or something.. NOTE : THIS LINK IS A DIRECT DOWNLOAD..
USE / DOWNLOAD AT YOUR OWN RISKMicrosoft Windows Server 2008
Have fun.. and remember this is beta
it'l time out in June 2008.