Tired of those pesky gridlines being displayed onscreen? Here's how to turn them off.
Thanks to Marek for pointing this out -- I like to consider myself the queen of "it's under tools > options" but I only looked under the View menu before resorting to hack measures.
Choose Tools > Options > Calc, View. Deselect Grid Lines. You can change the color of the grid lines here, too.
Note that by default, they don't print. To make them print, choose Format > Page, Sheet tab.