(Yet another interesting eavesdropping gadget. From the seller's ad...)
"Bionic ear allows you to hear a conversation from across a crowded room.
With the Spy Ear II, you have access to the latest technology in audio spying. Its mini size, lightweight and skin tone color allow you to hear from great distances without anyone knowing that you are wearing it. The ultra-sensitive microphone allows for crisp, clear audio all in a discreet, tiny earpiece.
There is a volume adjustment that allows you to easily change the volume and hone in on certain conversations.
Simply put, this tiny, cutting-edge device will turn any average Joe into a secret agent." (more)
If you see someone with this, sneak up behind them and snap your fingers.