We all need something to aim for -- find your ideal challenge and start training for it.

For some, it's a fitness event such as running for a cause or completing a triathlon simply for the satisfaction of saying you did it. For others, it's something simple like being able to walk up a flight of stairs without getting winded. Yet others have even loftier ambitions -- Jessica Biel, for instance, plans to climb Mount Kilimanjaro.

But whatever your ultimate aim, make sure you have a tangible, attainable goal to work towards -- otherwise, you're just treading water. The most important aspect of your goal is that it has to be doable. If you haven't so much as walked around the block in years, don't pin your hopes on running the New York Marathon -- it will take years to get to that level. Instead, set a goal of running a mile without stopping. Once you've done that, increase it to five miles and so on. It will take time, but eventually, you might be climbing Mount Kilimanjaro, too.