"Plastics" may have been a famous punchline in The Graduate (1967), but plastic was serious stuff to French architect/artist/theorist Jean Maneval. In 1964, he designed a Bubble House ("Bulle a Six Coques") constructed of six interlocking reinforced polyester shells that could be easily transported to and set up at the chosen home site.
Available commercially in 1968, Maneval's houses came in white, green, and brown—colors that would blend easily into the landscape. Only thirty were ever produced, several of which were used to house visitors to a vacation spot in the Pyrenees. From the outside, the Bubble House looked like nothing so much as a downscale version of Monsanto's House of the Future, which was on display at Disneyland from 1957-1967; indeed, its petite size may have been drawback. Of course, when I imagine a plastic house, all I can think of is the delightful atmosphere inside a porta-potty. Look at more pictures here and here.