This example uses Google Chart APIs to create Geo-spatial heatmap. It doesn't need extension and would not cause extra charge from Google (Chart API is free but Map API is chargeable for commercial usage). It is almost just copying & pasting to use it in your own application.
BTW, This example is based on real World Health Organization(WHO) data, you probably can find some facts about alcohol consumption that you didn't know before. Enjoy it.