I always think it's interesting when I come across ideas for themed gardens.
For example, there's this post I did a while back about creating a Shakespeare garden, with plants from the Bard's works: http://www.longandshortreviews.com/uncategorized/spring-is-bustin-out-all-over-leslie-soule/
Also, I work sometimes on weekends in the garden center at a store that references the Western Garden Book for plant information. On page 115 (it might be different for more recent versions), it mentions a thing called a Moon Garden, with plants that show up best under the light of the moon, like white flowers. The image above shows one such Moon Garden.
Then of course, there's my little Hunger Games garden, which only contains Rue and white roses, thus far.
At any rate, I adore the idea of themed gardens, and I look forward to trying them, come spring.