The RFID Guardian is a personal, battery-powered RFID firewall that manages tags "within physical proximity of a person," blocking them from answering queries—and possibly getting snooped. Better yet, it can clone your chips so you can switch the signal off and on at your command. The latest version is totally open with a wiki, source code bank and bug-tracker, making an already fantastic tool—given the proliferation of RFID chips loaded with personal info—even better. [RFID Guardian via BoingBoing]