I'm fairly social so I found that my regular life was enough. Linus loved being carried and was very quiet as a puppy, so I took him out in my arms to all kinds of places and let people handle him. He was in class by 10 weeks, twice a week, and was exposed to other dogs, puppies, kids, men, women, etc. Also, everyone loves a puppy, so he was able to go into places where an adult would not be welcome, including a couple bars/restaurants and my office (gotta take advantage of the cuteness window!). I have friends living in a variety of environments, so he went to homes with yards, rural homes, and even a few buildings with elevators.
Some of the breeders in my club have puppy parties when the puppies are around six weeks. They have a handful of families over, break out the wine and cheese, and we handle all the pups. Heaven!
It's not a bad idea to have a BBQ, wine and cheese, potluck, card game night, etc. when you have a puppy. Good excuse to hang out with friends, eat, drink, and talk dogs.