http://www.esri.com/apps/products/download/index.cfm?fuseaction=download.all#ArcGIS_API_for_JavaScri...
If you need to use a local version the downloadable version is ready and available here:
http://www.esri.com/apps/products/download/index.cfm?fuseaction=download.all#ArcGIS_API_for_JavaScri...