Burn them at the stake while their henchmen watch and then bury the henchmen alive while handcuffed to his corpse with just enough space and light for them to see what's happening. Or just bury the lot alive with a bit of space and light, plus chuck in a few snakes as an added extra plus build in a camera to catch the event for the internet...
Then when it's all over open a hatch and pour in concrete to seal them in and build a bridge or something on top.

Or maybe drop them in the sea with a few sharks around and add a bit of bait... Again use a camera to record the fun for the web...