Whenever new technology steps in, we usually run for its sample database to test it features, functionality & enhancement, etc. When I started testing SQL Server Hekaton, I was looking for some sample databases. Finally, I grabbed it from msdn but there, it is script only. So you need to copy and execute it but if you need a downloadable version, you can download it from here (Northwind database).
Note : Make sure you have data folder in c: drive (C:\data)
SQL Server Portal 