Tower of Power is an alternative map to the famous Temple of Notch, it is similar and different in many ways.
Temple of Notch - When you first arrive there's a hole where you can drop items in. If you drop it on the left pressure plate it will grant you stuff while the one on the right gives you death.
Tower of Power - When you first spawn you will see a sort of pyramid shape made out of stone bricks. Sitting on top of it is the Ledgendary Butter Block, The giant structure on top is the Power Crystal. If the player walk up and touch the Ledgendary butter block power will be granted to them. After they touch the block 3 seconds later zombie pigmens will get rained down from the sky. They will hit the ground and die of fall damage leaving their dropped gold behind. Just keep touching the Ledgendary Gold Block until you feel like you had enough power. To stop the power cycle simply just get away from the tower and pick up your gold. Here's a picture and a video showing you how it works.
My zombie Pigmen is retextured to Steve due to playing an adventure map :-)
It uses some hardcore coding and a Spawner. The Spawner has a radius. And the edge of the radius is right where the gold block is. If you "touch" the gold block it will trigger them to spawn in mid air and fall down and die leaving their gold behind