Fallout: New Vegas REPCONN Rocket
This easter egg references Bethesda / Obsidian game, Fallout: New Vegas.
To the north of the map, right off the highway just west of the northern most convenience store is a small 1950’s styled diner called Up-N-Atom.
Once at this location players will notice a large, old-fashion style rocket ship to the right of the diner. Simply walk right up against the rocket and turn your volume up to hear the sound of a Geiger counter.
Fans of Fallout: New Vegas will probably remember the mission for the Bright Brotherhood (a cult of ghouls) where Chris Haversam, the fake ghoul, instructs the player to retrieve 5 rocket souvenirs from the Dino Bite gift shop in Novac in order to get the rocket ships up and running again.
It turns out however that these little toy rocket ships which were initially sold by REPCONN are actually radioactive, therefore giving off a geiger counter reading when you enter the Dino Bite gift shops storage room where they’re kept. Hence, the geiger counter sound in GTA V.