Google Maps
This xkcd isn't too far from my experience with Google Maps during my recent road trip. It saw into the future (I-840 in NC didn't yet exist, and "Future I-840" ended at Exit 19 where Google Maps told me to get off at Exit 21), and it didn't see into construction (I-95 didn't have an exit 351C in Florida). I guess this is why they recommend a sanity check at the bottom in fine print on all their directions.