One of the nice things about Google Calendar is the fact you can share your schedule with other people. However, if you'd prefer a more real-world solution, DIY enthusiast Alex Forey shows off how to create a little sign for your door.
Forey's build shows your current schedule on a small LCD screen using a Spark Core. This way, someone can just walk up to his door and see exactly where he's at. This is probably most useful in a household, but it could be handy in other places as well.
Google Calendar Door Sign [Newfangled Me]