I start by making a few sentences, with ___s here and there. The next person fills in all of the ___s with icons, then we laugh over it until somebody makes a new one.
Act like an idiot
Use incorrect grammar and spelling
Go into Grammar Nazi mode
Onto the actual game:
So I was walking along one day when I saw ___. I attacked it but a ___ saw me, so I used my ___ to kill it, then ran away to mine some ___. I found a ___, then fell into some ___, where I was killed by a million ___.
Edit: Also, if anybody can supply me with icons that we can use to place in the sentences, that would be great! If not, I guess I could rip them out of the actual images in the minecraft.jar.