There are numerous new policies and innovations in our government today, the most recent being the passage of the Affordable Care Act. Although the concept of universal healthcare isn't a new one, the employ of any similar system (even one as convoluted as the ACA), is quite a change for our government.
Another example of an innovation implemented by our government is the Tennessee Valley Authority, in which the government produced electricity and then sold it, creating a benchmark for energy prices throughout the country.
One idea that I've fallen in love with is actually a modification and an improvement to the already prevalent public transit systems present in most of our major cities. I would outfit a fleet of buses with solar panels as well as hybrid engines akin to those in cars, the combination of which should make the cost of fuel a non-issue when compared to current fuel consumption in modern transit systems. In addition, I would run this system much more often than most conventional systems, allowing for safer transport (would run through the night), as well as more consistent, reliable, and more readily available transport - saving the people in my city money, as they would not need to pay for their own vehicle and fuel, as well as time spent in unpredictable traffic situations.