I just discovered the promising Clear Congress Project today, which visualizes legislative data by political party and other other variables in real time. A mission statement from the developer: 

With the expansion of the Internet and computing technologies, the amount of data generated and recorded has increased exponentially. Recently, government initiatives, non-profits, and news organizations have created easily accessible sources for the large amount of data created pertaining to government institutions. However, government organizations too often mistake access for transparency and news organizations have been reluctant to adopt innovative news delivery formats better designed for their new role as producers and distributors of not just stories but also data. Clear Congress Project (CCP) leverages real-time data sources and information visualization techniques to serve as a model that realizes transparency as a process beyond data access and offers a new format for news distribution.

(via Chip Oglesby)