Traveling to the Computer Lab

Here's an incredibly obvious idea that took me nearly eight years to come up with:

Whenever I want my classes to meet me in the computer lab, I've always scrawled a note and taped it to the door. This is inconvenient and takes 2-3 minutes every time, which is incredibly wasteful. It finally dawned on me to create a permanent solution.

We have two labs in our school: the "Main Lab" and the "Keyboarding Lab." I made double-sided signs for each class (one side for each lab), and printed them on paper in the color I have assigned to that particular class. Then I slid them into sheet protectors, and attached them with a book ring:

I placed a command hook behind my door to hold them when not in use, so that they are always exactly where I need them:

I hung two more command hooks (I LOVE command hooks, by the way - they rock!) on the outside* of the door itself, so I never again have to bother with tape.

Again, kind of a "duh" idea, but one worth sharing - I can't be the only one tired of slapping handwritten notes on the door.

Anyone else have something obvious yet helpful to share?

*If you happen to work in a building where there's a healthy chance anything you attach to the outside of your door will disappear, you'll want to hang your hooks on the inside so that the sign shows through the window. Just saying.