Yeah, your definetly right about advanced literature stimulating the creative process. Some other things I've found that helped are visiting an art museum, engaging in intellectual conversation/debate, playing chess, attend a lecture, and listening to music that requires your full concentration; chick Corea, Micheal Brecker, Chris Potter, etc....I find stuff in odd time signatures and stuff based around exotic scales to be quite stimulating.

Stimulating the brain can be quite an inspiration....and when you think about it whats the biggest brain stimulator of all thats been the basis of many songs.....Love.