And if you're interested in how the thing works, I'll let the Dodo explain:
`What I was going to say,' said the Dodo in an offended tone, `was, that the best thing to get us dry would be a Caucus-race.'`What is a Caucus-race?' said Alice; not that she wanted much to know, but the Dodo had paused as if it thought that somebody ought to speak, and no one else seemed inclined to say anything.
`Why,' said the Dodo, `the best way to explain it is to do it.'
Actually, that wasn't very helpful, but CNN has a primer that will keep you from grabbing the nearest bottle marked "drink me".
Happy Iowa Caucus Day!