Extremely close examination of the impulse drive system schematic panel in Main Engineering might reveal that one of the components is labeled “Infinite Improbability Generation,” a tip of the hat to Douglas Adams’s Hitchiker’s Guide to the Galaxy.
Mike Okuda, Star Trek: The Next Generation Technical Manual.
Apparently when the blu-ray disks come out, we’ll be able to see these panels, some with in-jokes never designed to be visible on television, in high definition.
Read more from Mike in this interview from Star Trek.com.