[whpalmer4]

They apparently haven't elided the "trial license" text from the web page everywhere, but OmniGraffle now has a 14 day demo period, and is fully functional during that period. You just download it and use it. However, if you've previously done so, and the 14 days has gone by, you're not going to get another 14 days just by downloading it again to the same account on the same computer.