The “Joyrider” is a LED-based crystal wheel attachment that uses built in sensors to determine wheel speed and blink rate to produce the image of a smiley face that stays upright and stationary in the wheels as you roll.
Read “more” to see static pics of the piece and get the link to the designer’s site…
Not sure if these are going into production.  These two units were sold at auction at hte ICA 2008 Gala: Figures of Speech for £2000.  Check out designer Moritz Waldenmeyrer’s site here, and this product’s page here.