What it does: This free plugin from Microsoft allows Excel 2010 to handle massively large data sets much more efficiently than the basic version of Excel does. It also lets Excel act like a relational database by adding the capacity to truly join columns in different tables instead of relying on Excel's somewhat cumbersome VLOOKUP command. PowerPivot includes its own formula language, Data Analysis Expressions (DAX), which has a similar syntax to Excel's conventional formulas.
What's cool: PowerPivot can handle millions of records -- data sets that would usually grind PowerPivot-less Excel to a halt. And by joining tables, you can make more "intelligent" pivot tables and charts to explore and visualize large data sets with Excel's point-and-click interface.
Drawbacks: This is limited to Excel 2010 on Windows systems. Also, SQL jocks might prefer using a true relational database for multi-table data in order to build complex data queries.
Skill level: Intermediate
Runs on: Excel 2010 on Windows only.
Related tools: Zoho Reports can take data from various file formats and turn it into charts, tables and pivot tables.
What it does: This general-purpose visualization platform allows creation of interactive dashboards with multiple, related visualizations -- for example, a bar chart, scatter plot and map. The open-source project was created by the University of Massachusetts at Lowell in partnership with a consortium of government agencies and is still in beta.
What's cool: The visualizations are slick and highly interactive; clicking an area in one visualization also affects others in the dashboard. The platform includes powerful statistical analysis capabilities. Users can create their own visualizations on a Weave-based Web system, or save and alter the tools and appearances of visualizations that have been publicly shared by others.