Lifehacker's Adam Pash has five really sweet little tips for getting the most out of Google new Command Line tool, which allows you to manage a wide variety of Google services from the command line.
Quickly Add Any Event to Google Calendar with Plain Language
You can quickly add any event to your Google calendar with GoogleCL with one command and plain language. For example, if I were to simply type:
google calendar add "Dinner tomorrow at 8pm with Ellen at Figaro"
…and hit Enter, GoogleCL will create the event in Calendar and figure out what I meant about the when and where. It's the same Quick Add feature available on the Google Calendar site, but you don't have to fire up your web browser and wait for Calendar to load to use it. You can enter the who, what, where, and when, and Google Calendar will figure out the rest.