According to Official Guinness Records,
The longest videogames marathon playing on a Just Dance game is 138 hr 34 sec and was achieved by Carrie Swidecki (USA), who played Just Dance 2015 (Ubisoft, 2014), at Otto's Video Games and More, in Bakersfield, California, USA, from 11 to 17 July 2015. Carrie was attempting to break her previous record for charity.
For a complete list of 2015 records, please visit 2015 Guinness Records in United States.