Rich kids "slumming it" and thinking they're being cool by smoking pot and living out their "creative" fantasies that usually don't come to anything, in between travelling to exotic third world places like Bali, Morocco, or Thailand, more or less like a cross between a
neohippie and a hipster (although there is considerable overlap between trustafarians and both of those other subcultures) commonly found in the Venice,
Echo Park,
Atwater Village, and
Silver Lake neighborhoods in L.A. (although Silver Lake is getting a bit too expensive for all but the wealthiest trustafarians, so some are going to Hollywood and assuredly some will go to Koreatown soon if they haven't already). The term is derived from a combination of "trust fund" and "Rastafarian".