The Political Compass
A couple years ago the µTorrent guys pointed me toward the Political Compass, and I have since had a lot of fun with it.
The Political Compass gives you a series of ideologies to choose from, and uses them to map you on two axes: an economic scale (left/right) and a social scale (authoritarian/libertarian).
Many of the questions in the test forces one to take a deeper view at their own ideologies. I know there were a couple on there that made me question myself. If you take it truthfully—ignoring any political parties that have slighted you, ignoring any political correctness, and simply answering how you actually feel, you might learn something about yourself.
The ideologies proposed are often on a far axis, forcing you to choose between extremes. Some of them are vague, forcing you to think it out. I almost universally have people paste me some of the questions with a big WTF, sometimes even accusing the test of being slanted against them.
It always fascinates me to have other people take it, because by the end most of them realize the guy they had been rooting for—Obama, McCain, Ron Paul, whoever—is actually pretty far from their views. Many Democrats realize they are a good deal farther left than they thought, and most Republicans find they are quite a bit more libertarian than they believed.
The compass is not really a definitive answer for what party you should vote for, I wouldn't recommend anyone vote solely because of it. But it can offer a starting point point for people, to filter the feel-good politics that try to appeal to everyone from the actual issues that people disagree with.
In a couple cases the people I've had take it realized they are actually polar opposites of the guy they voted for, one of them thanking me a few weeks afterward as it had caused him to read up on his choice and notice he had been fooled by those same feel-good politics, saying "I can't believe I almost voted for that idiot!"
