Windows RT easy (thethered) jailbreak tool released
The original method was found by Clrokr (who was then applauded by Microsoft for his efforts), but the jailbreak tool comes from XDA senior member Netham45. With the tool, jailbreaking your RT tablet is as simple as running the .bat file on your device and following the instructions. The one downside is that it is still a tethered jailbreak (for lack of a better term), meaning that you lose your jailbreak when you reboot your device. So, the jailbreak would have to be run again each time you reboot, which isn't too hard.
So far, there are only a handful of unsigned ARM apps that are available for installation, but that ecosystem should grow as long as this jailbreak is functional. There are a few interesting choices for unsigned apps, including an x86 emulator, PuTTY, 7Zip, and a VNC server/client.
If you want to try out the jailbreak, you can find the file and instructions in this XDA thread. And, if you want to try out some unsigned apps, you can find those in this XDA thread.
source: The Next Web