dealextreme.com and it came in the mail from Hong Kong about 2 weeks ago. The idea is that you press a button on this device and it's supposed to create a dead spot within a 30ft or so radius, effectively blocking cell phone signals within that range. Shit's illegal in the United States.
"Cool," I thought. Only this baby came dead on arrival. Wouldn't hold a charge, which was apparently a common problem. Serves me right for buying illegal electronics from China. I spent about the next week or so sending it back for a new one and having a back-and-forth with the English-as-a-second-language customer service reps.
Finally, a new one came back in the mail, and this thing is cool as hell. I feel like a god, terminating communication whenever and wherever I see fit. I have mostly used it at work for when there's a customer next in line on their phone and they just won't end it. Although it takes about 30 seconds or so to start working after I press the button.
They go for about 27 dollars and everything on DX has free shipping. Worth it in my opinion.