With the addition of the new "Redstone Lamps", I decided to toy around with them. Long story short, I built a blink machine that hooked up to Redstone Lamps and flipped the switch. It caused a sharp decrease in FPS, which immediately subsided when i deactivated it. I'd like to see how it would function to grief servers and cause lag. It seems extremely effective.
Here's how I made it:
Layer 2 (top)
Layer 1 (Bottom)
Glass is a lamp, flower is redstone dust, torch is a redstone torch, and the log is whatever solid block you want.
Lamentably, I haven't a server that runs on the snapshots. So I can't test it, and I also don't have the program nor the motivation to make a video of it. If anyone does test and film it, I'd be very grateful.
The lighting engine is bugged in the current snapshot. They are half way towards between making all lighting get handled client side (to decrease the amount of data sent and lag generated), and there are some very large bugs visible in the current half finished version of this code (daylight generated when blocks are updated underground). It is quite possible that once client side lighting is finished this device will not generate network lag, and only create client lag on machines which don't meet recommended system requirements.