I love applications that serve their purpose with little-to-no user interface. Something as simple as adding a calendar to your desktop should not require much, if any, work on my part. Thankfully, there is just such an app available for the Mac, and it’s free! DateLine is a simple little app that packs just enough features into itself to make it as useful to use as it is beautiful to look at. DateLine simply puts a linear calendar on your desktop. There are plenty of calendar apps out there that can do this, but none I’ve come across put them on the desktop horizontally, and look so good. 
DateLine’s preferences allow you to customize the color of the text, the lines and the color of the background. You can also adjust the transparency of all those items to suit your taste. Clicking on a date or the month, opens iCal and highlights that day in your calendar. The only issue I had with the application was that when you choose to hide the dock icon in the preferences, you lose all apparent access to the DateLine application preferences. Not only does the icon not show up in the dock, but you can’t switch to the app with Command + Tab. This isn’t a big deal, because there’s little reason to go back to the preferences once you set them – but it’s still an annoyance that should be corrected. And apparently the developer knows this, because he quickly replied to my email regarding the matter. Not only is a contextual menu in the works, but he shared with me that you can indeed access the prefs by clicking on the DateLine calendar and hitting Command , to bring up the preferences. DateLine is Open Source, and free to use on any Mac running OSX 10.5 or higher.
