Since it's been mentioned a couple of times, a little note on Crossfit. It's not just a new workout plan or fitness class, it's a methodology! Crossfit is a 'general preparedness program' and you can do it as prescribed {and that works great}, but if you have specific needs or goals it is highly adaptable and can still retain the core of the methodology. Basically:
~ every time you workout, go as fast - strong -hard as you can
~ avoid repetition
~ try everything, olyimpic lifts, gymnastics, plyometrics, running, swimming, biking, etc, etc, etc
~ avoid repetition
~ work on your weaknesses, don't worry Crossfit will help identify them
~ avoid repetition
~ eat right, rest properly
~ your workout imagination is your friend, repetition is your enemy
How to get started on Crossfit? First go the web site {www.crossfit.com} and start reading the "Start Here" section, then start working out. Take a look at the scaled workouts to start with. Also sign on to the online forum {it's sort of like scubaboard, but for fitness ~ a good read}, then read lots and ask questions. See if there is a Crossfit facility near you and visit them. Even if you don't want to be a regular member of the facility, visit them and stop by now and then. I've visited a few and they are were all good places.
A work of caution, this is old school fitness. A lot of hard work, sweat and grit. You will have fun, but pay for it with improved fitness. There is no cardio step class, row upon row of machines, people talking on their cell phones while working out. What you will see is a highly motivated group of people {from all walks of life ~ just like diving}, working hard, helping each other, loud music, odd pieces of 'fitness' equipment and writing on the walls!
Good luck and enjoy.