do you mean you're looking for an example of something creative that the Mayas created that can be used now to demonstrate that they were creative? ( I don't know whether in the past the Mayas had to prove their creativity...)
A good example is the Maya script: the only script that can fully encode a language that we know of from the Old World. The Maya script, is also especially ornamental, and served also a decorative purpose; this is definitely a good example for Mayan creativity.