Flywheel
Riders hop on Flywheel'sbikes for a workout with climbs, descents and a weighted arm workout. Bethenny Frankel recently took a 45-minute class at Flywheel in L.A, calling it "a fun, efficient workout." Locations nationwide, and in Dubai too.
Surfset
Surfset mimics surfing—without the water. The instability of the board forces the core to continually react to a shifting platform, burning major calories and sculpting abs. Madonna's personal trainer, Nicole Winhoffer, is a fan.
SoulCycle
SoulCycle features inspirational coaching and an intense full-body workout. Fans include Kelly Ripa, Anderson Cooper and Katie Holmes. The first location hit NYC in 2006, with others now in the Hamptons, Westchester and L.A.
Cardio Fusion Barre
Exhale Spa's workout is designed to create chiseled abs, cut arms and a lifted booty. (Yes, please.) The ballet-inspired class focuses on alignment, flexibility and posture. Celeb fans include Allison Williams and Vanessa Hudgens.
Rockin' Model Workout
An only-in-L.A. fave, Graze Lazenby's class at Equinox combines a hot playlist, inyasa-flow yoga, pilates and dance. It's hard not to feel sexy when the trainer shouts, "Who are the most beautiful women in L.A.? Own it! Live it! Believe it!" Get it, girls.
Shockwave
Prepare to get your butt kicked. This circuit workout combines Indo-Row machines, body bars, BOSUs and kettle bells for sculpting. Stars like Bradley Cooper, Cameron Diaz and Leann Rimes are fans.