Spatial Analyst - Supplemental tools
With the introduction of the capability for sharing custom tools in ArcGIS 10.1, the Spatial Analyst team has endeavored to provide new functionality as a collection of script tools. These tools can be used as-is for the applications they are identified for, or you can modify them to handle specific use cases that you might have.
These tools are written and delivered as a Python Toolbox. For more information and help on getting started with Python toolboxes, refer to the ArcGIS Desktop help.