Find What You Love and Then DO IT!
I figured out a while ago that if I don't like something I won't do it and magnify that by 10 when it comes to exercising! Find what challenges you, makes you sweat and is something you look forward to doing 5 to 6 times a week. I love to dance so I got hooked on Zumba after just one class. Chances are a fitness center near you also offers Zumba and other group classes and usually you can try a class or two out for very little or no money just to see if you like it.
If you can't seem to get motivated to start exercising think back on what you liked to do when you were a kid and do the adult version of it. Do what makes you smile and laugh. Ride a bike, go hiking, rock climbing, jump rope or go swimming. Just don't grow roots and stay planted on your couch or recliner!