One of the new features in Word 2010 is tools on the Ribbon that appear on demand, as you work. These tools will appear automatically as you work in your document. They will be relevant to what you are doing at the time.
For example, if you are working with a table in your Word document, when you click in the table, you will notice that the Design and Layout tabs, along with the Table Tools, will appear on the Ribbon.
Another example would be if you were working with a chart in your document. When you click in the chart, you will see that the Ribbon now shows the Design, Layout, and Format tabs, along with Chart Tools.
When you click away from the table, chart, or other feature, the on-demand tools will disappear, and the standard tabs will remain.