My friend Roshan Godaliyadda told me about the political compass, probably the most successful political mapping I've ever seen. Rather than having a traditional right-left linear differentiation, political compass map people into a two dimensional map; one axis being the social policy and the other being the economic policy.
My friend Nuwan Subasingha did a wonderful job in his blog post on the political compass. Most valuable piece work he has done is the mapping of a wide range of popular politicians to the map.