My friend Kasper, who’s a PM on our team, has been posting a lot about the new features in the CTP3 release of PowerPivot. Here are some pointers:

PowerPivot CTP3: What is new for Time Intelligence functions
Denali PowerPivot: new DAX functions that will make your life easier
PowerPivot drillthrough in Denali CTP3
PowerPivot Denali: Working with multiple relationships between two tables
PowerPivot Denali new DAX function to rank (RANKX)
PowerPivot Denali: Parent child using DAX

He must have been saving them up… :-)