Jane Fonda's classic 1988 workout tape, still a best-seller, combines fat-burning aerobic routines with stretching and conditioning for lithe, toned muscles. Easily adaptable to fit in the busiest of schedules, Fonda's tape can be done all at once for a 70-minute, full-body workout, or you can break it down into three shorter segments: 35 minutes of aerobics, 15 minutes of upper-body conditioning, and 20 minutes of lower-body conditioning -- weights optional. Appropriate for all fitness levels.