Area 52???
Graffiti is obvious, i think that 99.99% of SA players know that they are real.
IDK about the other 00.01%...
Edit: Im not sure someone posted it but: If you take an AK47 and go into the Inn near Area 69 that has a flying plate on a stick (lol), if you enter and shoot the pool player in the head with the AK, he will run to you with a 0% health and will crash near the stairs.