My wife and I are going to the Braves game today, so my time to workout this Sunday morning was limited, especially since I didn't get out of bed early.  I hit the gym and did one hour of aerobic work....20 minutes on the stationary recumbent bike, 20 minutes on the rowing machine, and 20 minutes of fast hill walking on the treadmill.  It was definitely a time efficient and effective workout.  I may incorporate this one into my routine.