Here’s a popular fitness gift for fitness buffs: The BOSU Balance Trainer.
The BOSU stands for Both Sides UP and is a product that is round like a ball, but has a flat plastic surface for placing flat on the floor. Placing the BOSU on the flat side gives a person stability training especially for the lower legs and ankles. Placing the BOSU on the round-side down gives a person more stability workout at the hips and abdomen as the instability is felt higher up on the body when the round side is down.
The BOSU is also excellent for abdominal work — especially side or oblique work.