CICS (Customer Information Control System) was one of the first transaction oriented (interactive) system on IBM mainframes. Monitoring the performance (response time, use of disk and core space etc.) was a tedious task for one of my colleagues, who definetely needed a simpler method.
This device is just placed on the top of the screen with all the data shown an it immediately translates the rows and columns into a single number of Degree CICS. The device is covered in foam to survive throwing attacks from unsatified customers and angry programmers.
Expenditure of human labor: about ½h. The thermometre is from an old hot water heater. Of course it was easy to modify °C to °CICS …