To download versions of Adventure Works databases for SQL Server 2012, go to AdventureWorks for SQL Server 2012 on CodePlex.
AdventureWorks Community Samples Databases for SQL Azure
SQL Azure is the relational data store for the Azure platform. The SQL team has also released a AdventureWorks2012 Full database on CodePlex containing the full version of the AdventureWorks2012 database along with an AdventureWorks samples database that is scaled-out using SQL Azure Federations.
There are some other downloads available for OLTP, Multidimensional models, Datawarehouse etc. Do check them out!