Thanks to Andrew for flagging up a rare sighting online – of a Pong Clock by Buro Vormkrijgers, currently being auctioned on eBay.
As you can see, this is a clock based on the classic Pong arcade game. Only 400 were produced by Buro Vormkrijgers, all numbered and signed by the maker, all showing the time on the scoreboard – left player shows the hours, right shows the minutes.
Soon after the first batch were made, Atari (which owns the copyright) stepped in to stop further production, so the 400 made will be the only 400 in existence. Which makes this a real collector's piece. The one on offer now is 180/400 and is up on a 'buy it now' for £699.99. Not cheap, but as something unlikely to be made again, possibly a shrewd investment.