PowerPivot and DAX papers,posts,FAQs,webcasts,samples

I had an interesting question today where someone send me a workbook that contained a flattened table like this:

Now as a result we want to see the top 1 nr of products per country. The problem here is that we cannot just load this data into PowerPivot and start analyzing to get this result. In this case the columns need to become attributes in a dimension. This is a classical ETL operation that can be done by many tools like SQL and SSIS , but not by PowerPivot as a modeling tool.