My favorite has always been "The Random damage table." Was geared as a tool for killer DM's. "Why waste time rolling up random monsters with which to kill the party. Just use the random damage table to roll up an amount of damage and cut out the middle man."
Two of the results I remember:
Roll all the dice the player owns. Add the results. Character takes that much damage.
Roll all dice within 30 feet of player. Add results. Character takes that much damage.

Two of the results I remember:
Roll all the dice the player owns. Add the results. Character takes that much damage.
Roll all dice within 30 feet of player. Add results. Character takes that much damage.
