The Null Device
Cow Clicker: a distillation of addictive, potentially expensive Facebook games to their purest essence:
You get a cow. You can click on it. In six hours, you can click it again. Clicking earns you clicks. You can buy custom "premium" cows through micropayments (the Cow Clicker currency is called "mooney"), and you can buy your way out of the time delay by spending it. You can publish feed stories about clicking your cow, and you can click friends' cow clicks in their feed stories.
The Chipophone is an instrument for live chiptune performance (i.e., playing live music on a keyboard in the style of music generated by 8-bit computers and game consoles), made from microcontrollers and housed in the chassis of a 1970s-vintage electronic organ by a Swedish chap named Linus Akesson. There is a video of Akesson demonstrating the unit and its features, and playing some classic chiptunes live, here.
Pay & Sit is a user-pays park bench. The bench contains metal spikes embedded in the sitting surface, which are retracted when the user inserts 0.50€ into a coin box; the bench beeps when the sitting time is about to expire.
Pay & Sit is not an actual product, however, but the work of an artist named Fabian Brunsing, commenting on the logical extremes of user-pays culture and/or the privatisation of public space. There is no guarantee, however, that some local authority (or some firm contracted to manage (privatised, ad-funded) public parks by one) won't try something like that at some point.