From the Center for Disease Control H1N1 "Questions and Answers" page:
What is CDC’s recommendation regarding "swine flu parties"?
"Swine flu parties" are gatherings during which people have close contact with a person who has 2009 H1N1 flu in order to become infected with the virus. The intent of these parties is for a person to become infected with what for many people has been a mild disease, in the hope of having natural immunity 2009 H1N1 flu virus that might circulate later and cause more severe disease.
CDC does not recommend "swine flu parties" as a way to protect against 2009 H1N1 flu in the future. While the disease seen in the current 2009 H1N1 flu outbreak has been mild for many people, it has been severe and even fatal for others. There is no way to predict with certainty what the outcome will be for an individual or, equally important, for others to whom the intentionally infected person may spread the virus.
CDC recommends that people with 2009 H1N1 flu avoid contact with others as much as possible. If you are sick with flu-like illness, CDC recommends that you stay home for at least 24 hours after your fever is gone except to get medical care or for other necessities. (Your fever should be gone without the use of a fever-reducing medicine.) Stay away from others as much as possible to keep from making others sick.