Whitepaper and Samples Released: Data Analysis Expressions (DAX) In the Tabular BI Semantic Model

If your looking to get into DAX and the tabular model but not sure where to start or where dax fits in, theres a new whitepaper released.  It gives a good overview and will get you started in no time.

http://www.microsoft.com/download/en/details.aspx?id=28572