Crossfit has been another recent workout craze.  It's been described many ways, but I think the essential idea is that you go hard and fast at whatever it is that you are doing that day.  Some workouts can be done in about 10-15 minutes, but they will crush you because you push so hard.  The workouts vary from things like rope climbs to pullups to olympic style lifting.  If you can push yourself to do crossfit hard everyday, you will see fitness gains.