I really don't know if this would be easy or not but making it possible to drink milk so it gets you drunk. Its kind of just a joke but it would slurr your s and anything else that would make it kinda funny.
This plugin has already been made :3 http://forums.bukkit.org/threads/fun-muddersmilk-v1-4-add-alcohol-to-your-milk-1000.17015/