To be fair, they're not claiming sparklines itself, rather the integration of sparklines into a spreadsheet. That still doesn't seem useful and nonobvious to me, and on top of that there seems to be prior art, but don't mischaracterize what they've patented.

The patent itself: http://www.freepatentsonline.com/y2009/0282325.html

[Update] Having read the claims more closely, it seems the patent might be misnamed. Claims 1-12 and 14-15 make no mention of a spreadsheet at all, only the embedding of sparklines in an electronic document and autogenerating them based on data in the document. Claims 13 and 16-20 are the only ones that cite a spreadsheet.