I new feature in Excel 2010 is called SparkLines. These are basically charts that are contained inside a single cell.
Sparklines are mostly a visualization helper that can assist you to make sense of a set of related number, like sales per quarter for the last 4 years. Being able to visualize this information helps to figure out trends etc easily. Also since these are inside a cell you can actually have a separate column or row that just contains Sparklines thus able to present the visual representation for a huge volume of data that would be very difficult using individual charts.
I created a small video that show how this feature works. I have used publicly available US consumer credit data to show how the visualization helps (Though the data really only goes one way, up ).