HTC Sense is one of those things you either love or loathe. Much more than just another launcher, Sense is a complete framework replacement, with so much of the Android system being integrated into Sense. Some people like Sense so much that they spend a significant amount of time and effort in porting it to other non-HTC devices.
Enter XDA Recognized Developer Zackconsole, who has managed to port HTC Sense 4.0 to not only one device, but a number of Sony Xperia devices. Before you Xperia owners get too excited, the ROMs are still considered very pre-alpha, meaning they are far from complete and not usable for any real purpose. They are intended for developers only at this stage, or for those hardcore flashers who just have to try new things. But this is definitely amazing progress and goes to show nothing is impossible.
The list of working features is quite small at the moment, hence the pre-alpha status:
If you think you can help with the development of these ROMs, or just HAVE to give them a try, head on over to the thread relevant for your device: