[nine_k]

Connecting 100k LEDs to a RPi is an interesting engineering challenge in its own right. (Also, if one LED consumes 10 mA / 30 mW, 100k will consume 1000 A / 3 kW.)

A more realistic thing would be a telnet chat server: code is dead simple, and the ability to handle NH / slashdot / reddit crowd on a RPi would indeed be impressive.

[mschuster91]

Not exactly, there are many LED driver ICs with SPI, and you don't really need a 1000A-capable 3V bus, just 500 or so small wall-warts ;)

[forgottenpass]

Not lazy enough. Just talk Art-Net, the instruments are now Someone Else's Problem.

[mschuster91]

More lazy: attach yourself to one of these LED-based megascreens in sport stadiums. Output ordinary composite video and you're done!