Lovecraft Spotting: Fallout 3

Fallout 3 players: Spend some time at the Dunwich Building, which you can find in the southwest corner of the map.

Spoiler: As told through a series of personal audio logs, a poor soul, seeking refuge in the building, discovers a 'book', written by a certain Arab, which eventually turns him... well, you know the rest.

If it weren't for the ghouls trying to tear you to shreds, it wouldn't be particularly scary -- in fact, it would have been creepier if Bethesda had ditched the ghouls altogether. Still, the obelisk that the ghouls were (presumably) worshiping is pretty neat.

(Sadly, the Necronomicon isn't in the building -- or if it is, I couldn't find it).