As SQL Server 2012 and PowerPivot v2 release is getting closer and closer, knowing DAX becomes more of a necessity than a just an option. Via ’s blog I had learned of a nice 30 minutes Introduction to DAX basics. You can download an example workbook and try your hand at creating a measure formula and adding up to adding filter context to your formula. The post also had a ling to the TechNet Wiki page for the DAX Resource Center which has loads of articles, downloads and videos, along with link to other blogs and sites with more resources.
So you have all the resources you need to start learning DAX – now make those 30 minutes to actually do it 🙂