Turn a Raspberry Pi Into a Super Cheap, Packet-Sniffing Power Strip
Interesting project to convert a surge protector into a packet-sniffer via Lifehacker. For more critical coverage that includes worries about the electrical safety of the design, check Hack A Day here.
When you’re finished and plug everything in, you’ll end up with a surge protector that looks completely inconspicuous, but can capture any traffic to and from the system it’s connected to. You’ll have to come back to pick up the SD card periodically, but you could fix that by adding a Wi-Fi or 3G radio to the sniffer, drive up outside, log in, download your data, and drive away (of course, broadcasting wirelessly will increase your odds of detection and make the build bigger, so there are drawbacks.)