We've had a good time with the Necomimi Cat Ears in the past--we used them to monitor our interest in the last iPhone event--but the Good Times project is a use for them we never expected.
The Necomimi Cat Ears, upon which the Good Times project is based, use electroencephalography to monitor brainwave activity. The Cat Ears are a pretty simple cause-and-effect toy: with high levels of brain activity, the ears perk up. With low activity, they droop down. They're fun, but we couldn't see much real practical use for them.
Good Times uses essentially a pair of the Necomimis without the ears attached, and uses the brainwave monitoring to trigger a specific response when people try to call you. When your brainwave activity is very high, the device assumes you're mentally very engaged, working hard on something, and thus do not want to be disturbed. If anyone tries to call during that time, he or she will get your voicemail, which the headset has activated via Bluetooth. Once your brainwave activity has lessened, people will be able to get through again.