I added a link on the right side of my blog to find the sunrise and sunset time for any day past, present, or future. I just used it to see how much time I have left to mow the lawn tonight. I will have light until 8:49 PM CDT.

Look at the "End civil twilight" time, not the "Sunset" time. Sunset is actually a technical term for when the upper edge of the disk of the sun is right on the horizon. Not very useful is it. Civil twilight is how late useable light is available. Much more useful.