When was the last time you were really surprised by something you read? I mean, really.
Many of us tend to read mostly the same sorts of things - the same business journals, the same sorts of books that are written by the same sorts of people, and the same blogs we always visit. And, hey, that's better than not reading at all. But there's something better still, and that's to explore a bit of new territory, to try something novel, and dip into a different pool of water.
One of the most reliable wellsprings of creativity is exposure to new stuff. And that's sort of so obvious that we all already know it - but we need to be reminded of it, and of its importance.
But, rather than reading something new, you could of course just go somewhere new, and that also has its charms and potential effectiveness for sparking new sensibilities and thoughts, as long as you don't stay in basically the same hotel you check into wherever you go. But a new book is a lot easier to get to than a brand new place somewhere else in the world. They're all around. Grab one, and just try something very different, and see what happens.
The books outside my normal orb that have hit me the hardest recently are Gilgamesh, Beowulf, and Frankenstein, just to mention the short ones.
It works for me all the time. Really. And I heartily recommend it.