The keyboard exerciser is a robotic arm with hand - similar in appearance to [xenzag]'s "Nosey Parters" (link) - to be used with laptop computers.
Every time you power down the computer, the KE reaches across the desk, opens a computer's diplay lid if it was closed, and presses each key in sequence
and repeatedly for up to an hour (exercise durations are user programmable). Alternately, it could work on a scheduled basis when you're away, with the computer powered on, opening a text editor and repeatedly typing some preset phrases.
You may ask WHY? Or you may not, but I'll explain anyhow.
Consider a "laptop" computer used as a desktop replacement. It likely spends most or all of its life connected to external keyboard, mouse, and displays. The built-in keyboard rarely if ever gets used. The plastic membrane under the keyswitches never gets flexed. And if the lid is closed most of the time, that membrane gets exposed to much more heat than it was originally designed for.
Over time these components degrade - and the user, on the rare ocassion they need to actually USE the internal keyboard, wonders why it doesn't work very well, if at all. Some keys stick, some don't register unless hit very hard and perfectly on center.
The keyboard exerciser makes sure your keyboard gets all the fresh air and exercise it needs, so it's in good shape when you want to take it out to play.