Microsoft's got a hit on its hands with the Windows 8 Metro UI. It's clean, fast, and intuitive. It's so good, it makes other more popular mobile operating systems look a bit staid. If you want to try it out before the next-gen tablets hit stores or are hesitant about getting a Windows Phone device, you can now run the Metro UI right on your iPhone via a mod for jailbroken phones called Metroon.
Metroon more closely resembles Windows 8 as opposed to Windows Phone 7 in that you can scroll horizontally instead of vertically. Metroon is available from ModMyi for $1.50. JailBreak Nation put together the above video that outlines how Metroon works and what users can expect from the modification.