Urine typically is a shade of yellow. There are a few disorders which change the color of urine in a dramatic way. To be specific one should see their doctor. Generally when urine gets brown or Coke colored it suggests a liver or bile duct problem.
Red urine can be blood or can look red from certain medicines.
Black urine is classic for a genetic defect. The shades of yellow of urine are usually related to the concentrated of urine. If you swallow a vitamin B2 supplement, and the amount is more than your body needs, the vitamin is excreted in the urine. But there is nothing wrong with you when this happens - it is just your body getting rid of extra vitamin B2. Some health authorities use this as an example that taking large doses of vitamins only makes expensive urine.