To make your excel sheet a tad fancier you may want to use some king of image as a background in excel sheet.
This post demonstrates how to insert a background image in excel sheet in couple of quick steps.
Go to Background icon in the Page layout tab as shown below.
Click on background and you will get a pop up to select a picture to insert as a background image in excel sheet.
Select a picture to set as a background in excel sheet from your machine.
And click insert. Now you have the picture as your sheet background.
Hope this helped.