Haha... if ever there was a question that didn't need asking, I would have thought it this one based solely upon the sheer number of senseless polls we see. Seriously though, my guess is it's very easy to do when starting a thread.
That's easy! Just start a thread and proceed to the bottom of the thread. Just make sure that your poll makes sense and includes all possible options that the voters may come up with. Otherwise, someone is liable to make fun of your poll. Chris