Every 10 minutes, for 40 minutes (4 sets) for times:
40/30 Calories of Assault Bike/Row or 50/40 Schwinn Bike
Modify the workout appropriately such that you get between 2-3 minutes of rest between sets. The intent is smooth pacing and four sets that are very similar in time. If you are running over the 8-minute mark, scale back accordingly.