A political houseparty is a party

Party

A party is a gathering of people who have been invited by a host for the purposes of socializing, conversation, or recreation. A party will typically feature food and beverages, and often music and dancing as well....

 held in a private home for the purpose of supporting a particular candidate, political party, or ballot measure, or to share information and opinions about an upcoming election.

Such events may be arranged as a dinner party, or with light or no refreshments in a more casual setting. In municipal politics, it is not uncommon for the candidate to appear at the event to explain his or her platform and to answer questions.

Supporters are often encourgaged to organize political house parties by the organizers of the political campaign

Political campaign

A political campaign is an organized effort which seeks to influence the decision making process within a specific group. In democracies, political campaigns often refer to electoral campaigns, wherein representatives are chosen or referendums are decided...

. Advantages include a stronger persuasive power than a lawn sign

Lawn sign

Lawn signs are used for local advertising. They can be used by business such as real estate and are popular in election campaigns in some countries. They are small signs that can be placed on the property of a business or on the lawns of a candidate's supporters...

 or political ad

Campaign advertising

'In politics, campaign advertising is the use of an advertising campaign through newspapers, radio commercials, television commercials, etc.) to influence the decisions made for and by groups. These ads are designed by political consultants and the political campaign staff...

because some information is coming from trusted friends, there is time to convey a substantial amount of information, and the event is interactive. The primary disadvantage is that the house party will only "reach" a relatively small number of people, compared to the time and money required to have it.