A commercial break is normally somewhere around two minutes, which is also great duration for a couple of plank reps.
The plank is a great abs exercise to target your core muscles.
Get down on the floor in plank position. Rest on your forearms and toes. Keep your core muscles tensed and maintain a straight position. Down dip or raise your butt. Keep your gaze focused on the floor without tensing your neck. Start by planking for shorter periods and then gradually increase the duration. To make the exercise easier you can rest on your knees.
Plank with leg lift. Same starting position as the regular plank. Lift one leg slightly off the floor and keep it elevated for a couple of seconds before switching sides.
Plank with extended arm. Same starting position as the regular plank. Extend one arm straight in front of you and keep it extended for a couple of seconds before retracting it and extending the other.
Side plank. Lay on the side resting on one forearm. Place your upper foot on top of the one resting on the floor. This can also be done on your knees.