Every keyboard has LEDs on it. By LEDs I mean the Caps Lock, Num Lock and Scroll Lock lights. These LEDs help you to know if you have Numlock, Capslock and ScrollLock enabled/disabled. While surfing, I came across a tool known as Network Lights. This tool lets you monitor network activity on your keyboard(upload/download) ScrollLock and NumLock indicators. Each LED will flicker when network traffic is detected.
The tool is pretty cool but if you would like to check your network activity, then you need to sacrifice the caps, scroll and num lock lights because they cannot be used to do two functions simultaneously. The tool is compatible with Windows XP, Vista and 7. I checked the tool on Windows 7.