Network Lights developed by Igor Tolmachev is a Windows program, which blinks keyboard LEDs (Light Emitting Diode) indicating outgoing and incoming network packets on network interface.
Network Lights lets you monitor network activity (upload/download) from your keyboard ScrollLock and NumLock indicators. Each LED will flicker when network traffic is detected.
Network Lights can be downloaded from here.
Pretty cool haven’t seen a program like this before!
I once tinkered with serial/LCD to imitate this “just because”. This is a neat/entertaining application.