Yes.  Select it and it will show size handles which you can grab and use to
stretch the box.

The size of the legend key varies with the font size of the legend entries.
There is no way to increase the legend key's size while keeping the legend
entries the same size. (Well, you can increase the font size of the entire
legend, and reduce that of the individual entries, but I think once all
legend entries are the same size, the legend text size updates to the shared
size.)

- Jon
-------
Jon Peltier, Microsoft Excel MVP
Tutorials and Custom Solutions
Peltier Technical Services, Inc. - http://PeltierTech.com
_______

Hi Tara,

You can do it.  

1.  Add a dummy data point to you series and give it a name like "Dummy" but
no value - 0.  
2.  In the Legend select the Legend Entry for the new datapoint and increase
the font size.  This will increase the font only for this one point but it
will increase the Legend Key size for all the data points.
3.  Select the Legend Key for this data point and double-click it and in the
Format Legend Key dialog box set Border to None and Area to None.  This will
hide the Legend Key for this data point.
4.  In the spreadsheet delete the text "Dummy"