When they say to eat 5 colors of fruits and veggies a day, do they mean outside color or inside? Ie: watermelons: green? White? Red? Apples/cukes?!?

Variety counts. The point of trying to eat from all five colors is to give you a good assortment of antioxidants as well as other beneficial nutrients of vegetables and fruit. Many fruits or vegetables have the same color on the inside so why don't you go by the outside color. The main thing is variety more than anything else.
The part you eat! The idea of eating a rainbow of foods is that plants contain an amazing array of beneficial substances known as phytochemicals (plant-derived compounds). Eating plant-based foods with different colors helps a person get the full range of tese compounds. I'd go by the color of the part you eat - so watermelon=red. Cukes=green & apples=red or yellow if you leave the skin on.