Pet-peeve: People who completely disregard boardroom scheduling etiquette and squat in a booked room. Not only is this inconvenient over the course of a year but it can equate to a large amount of wasted money as legitimately scheduled users search the office for another available room. My answer is a cheap Raspberry Pi, connected to our WiFi network and running a Python app that talks to Google's Calendar API to get schedule information. The data is output to a low power 4x20 character LCD display and shows time to next meeting. Now there's no excuse to hijack a booked room.