Share24 Hour Fitness Founder, Mark Mastrov, Selling Cali Hideout for $14M By Jim LowensternPosted Wednesday, Aug 19, 2020 Mark Mastrov, the founder of 24 Hour Fitness, is looking for a buyer for his Lafayette, CA, residence. Tags san franciscolafayettecalimark mastrovmastrovfor sale by ownersingle-familycontemporarycustomj gornyvillavaulted ceilings4 bed6 bathmovie theatrehomeaquariumvideo gamebarpoolbilliardsputting greentennis courtbocce ballbasketballwaterfalllanai loungecave