Automatically create iron golems. All you need is a dispenser and fill it with carved pumpkins and iron blocks to be used for the golems.
You can activate the dispenser by looking at it and using the command:

/autogolem [count] [radius]

Read it like: "Keep the count of iron golems at [count] in the radius of [radius] blocks around the dispenser."

Every 3 seconds one iron golem can be spawned - of course as long as the dispenser contains the needed resources.
If you'd like to have it configurable, let me know.