Many photographers run out of photo ideas after a while, or get into a creative rut. For these times, I recommend the zoo!
The zoo offers an incredible opportunity to practice all of your photographic skills, with subject matter from around the world! You can practice your long lens technique before you spend $5000 on that African safari and get used to your tripod or monopod before you're in the Canadian rockies with the last rays of the sun illuminating that moose.
If you return to your local zoo often, you will learn when and where the lighting is best and when the animals are at their best. At the San Diego Zoo, the late afternoon light is wonderful on Horn and Hoof Mesa. I shot this antelope a number of years ago, before they were moved to the Wild Animal Park. I exposed for the animal, and positioned myself so the background would be in shadow, giving dramatic lighting to the scene.
You belong in the zoo!