A glorious machine that can be turned on and off that spawns creepers, captures them, brutally murders them, picks at their guts for their items, and give gunpowder. Try the save file!!
WHY IT NO LONGER WORKS
=======================
The cannon used an advanced minecart system to deliver a feed of
minecarts off a stack. When a pig was called, it boosted a cart off the
stack. Notch has [:'(] apparently removed minecart side-bump physics to
fix the booster miracle
bug, so carts no longer boost off the stack. But wait? You're probably
saying "But ChrisPerson, you could have used powered rails instead! It
would make it so much faster!" Well that would work, except that when on
a track, minecarts just fall over on top of each other and form into
one minecart, where there really is several. With a pressure plate below
them, they stack properly.
Oh,yeah, and the mods for this to work have been discontinued. Sorry, creeper haters.