Desperately awaiting the release of a jailbreak for Apple TV 3? It may take a while, you know that, right? Meanwhile, how about digging your old, already jailbroken 1st gen Apple TV out of the closet and supercharging it with the newest aTV Flash? FireCore has just released aTV Flash 4.5 for the original Apple TV that includes support for Mountain Lion as well as a handful of general improvements and fixes.
original apple tv
The new update includes File Sharing (SMB Server) that allows you to stream non-iTunes media stored on your Apple TV (including media stored on external drives) to other devices including a second Apple TV (silver or black) or a Mac/PC computer.