This sign has 3 cards with a different location on each side, and a place to store your cards when not on the peg showing where you currently are. When there are no signs on the peg there is a default image (in my case "causing trouble"); this way the sign isn't just taking up space at my desk when I'm there.
I made my sign with a laser cutter, and I included the files I used so you can make your own. If you don't have access to a laser cutter, or makerspace with one, you could send the files to be printed at places like Ponoko or BigBlueSaw. I made this design so it can be stacked flat and shipped easily.
So, "where is Mike"? Read on to find out!