Save PowerPivot workbook as Analysis Services Cube
Easy approach, might be a killer feature of PowerPivot. Link here

 

Export SharePoint 2010 External List to Excel
Find code here

 

Office 365-Datenverarbeitungsvertrag mit EU-Standardvertragsbestimmungen nutzen
German Blogpost here

 

HTML5 Video Web Part for SharePoint 2010
Download code here

Viewing SSAS Member Properties within an an MDX Query Window in SSMS
Nice approach to view Dimension Properties of a MDX Query in SQL Server Management Studio 

Using Google Docs, Data Explorer and PowerPivot for Questionnaires

I am bit surprised that PowerPivot for Excel can also be used to show data from Google Docs (thanks to their API), e.g. to visualize data from a Web Questionnaire

Sparklines for Excel
Free Plugin enables sparklines for Excel

 

SkyDrive API available
Now you can develop applications for the free cloud offering from Microsoft (esp. for WindowsPhone and Windows8)