Making plans with the gang? Try grabbing dumbbells instead of drinks. The new trend of "semi-personal" or "group" training, pairing pros with groups of two to five, drives down the cost and ups the fun factor. "It's an awesome way to stay social with friends," says Debra Strougo of Fitizens. Try it at your local Bally Total Fitness. Also check out small-group Pilates, yoga and dance—the perfect way to bond while blasting fat. Round up your pals, or ask your trainer to hook you up!