I was late for work this morning, because I got stuck in Zeno's paradox.
Hiccups are caused by something that irritates the diaphragm and causes it to expand or contract in a spasm. There are quite a few things that can do this, as yoavdothan said in his answer. One of them is drinking alcohol. It is not only the amount that is important, also how fast you drink it, and how cold it is.