Easter Island Motel is the nickname of an easter egg based on Easter Island, an island located in the southern Pacific Ocean.
Easter Island is famous for its 887 extant monumental statues, called moai, created by the early Rapa Nui people. Related to this some references can be found in GTA San Andreas. In Pilgrim, Las Venturas, a motel's billboard, looks exactly the same as the moai. On the front gate of the motel a painting of moai can also be seen strengthening this reference. As Las Venturas is based on Las Vegas and which in reality has a lot of replicas of famous world landmarks. It would make sense for Las Venturas to have similar sights. Moreover, the replicas of the moais were made in Ingram, Texas.
Easter Island was mentioned as a concealed abode for Aliens by Steve Henderson on the Easter Island Coverup, narrating that the extra-terrestrial beings are seeking refuge under the hot bed of the island, awaiting for the Apocalypse.