The
essays of Ran Prieur opened my eyes to a lot of new perspectives on this world.
The Invisibles is mindfuckingly awesome, especially after researching all its references and inspirations.
Robert Anton Wilson's books are great, and so is Terence McKenna's work if you're into psychedelics and/or wild metaphysical speculation at all.
These are just the things that have been blowing the lid off my mind lately.