They're running a contest at the James Randi Educational Foundation for the most comprehensive explanation of a clip sent to them. To join, watch the clip and leave a comment.

I've taken a quick look, and it's a variant on "Frank's Box"– a device for receiving/producing EVPs. Apparently there are subtitles on the screen which could make you think that you're hearing things that aren't being said, so I'd recommend listening to it without looking at the video the first time.

Update:  Meant to say "Frank's Box", not "Ghost Box".

Actually, I think the JREF is trying to kill two birds with one stone. First, they're working on increasing user involvement by widening the writer pool and getting the commenters involved. Running a contest is often a good way of doing that. (Remind me to run a contest here. In fact, here's the first contest. First person to suggest a good contest idea wins a Skeptical Viewer T-shirt or comparable schwag. PM me; I don't want to hijack this thread.)

Secondly, they're getting some thorough explanations of the Shack Hack video without having to write it themselves. That's not a small task– it's often a problem to describe exactly what's wrong with a video even when you know perfectly well it's nonsense. The utter insanity of a claim can make it even more difficult. I mean, what do you say to someone that thinks they can listen to ghosts by flipping a radio around at random?

Finally (I guess that was three birds), they get to respond to the video without actually dignifying it with an official JREF response. That can be good for a few reasons. One is that unless they respond directly, there's no actual conversation, and so the JREF can just ignore any emails they want. They can't be accused of walking away from a challenge. (As far as I know, the sender hasn't actually applied for the JREF Million Dollar Challenge.)