If you are going to the beach, gym, or an outdoor area you are going to want a fragrance that is tropical, fruity-think citrus or those with marine notes. Notes such as neroli, Sicilian lemon, and jasmine are also great.
The fragrances should have good longevity and be light and bright. Essentially, it should give you a fresh out of the shower feeling.
Think of Dolce and Gabbana light Blue or Davidoff Cool Water for men and women.