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

Some parties are held in honor of a specific person, day, or event (e.g., a birthday party, a Super Bowl party, St. Patrick's Day). Parties of this kind are often called celebrations.

A party is not necessarily a private occasion. Public parties are sometimes held in pubs and bars, and people attending such parties may be charged an admission fee by the host.

Birthday party

A birthday party is a celebration of the anniversary of the birth of the person who is being honored. Birthday parties are a feature of many cultures.

In Western cultures, particularly in the United States and Australia, birthday parties are often accompanied by colorful decorations, such as balloons and streamers. A birthday cake is often served with candles that are to be blown out after a “birthday wish” has been made. While the birthday cake is being brought to the table, the song Happy Birthday to You is sung by the guests. Wealthy people and celebrities may hire an event management agency or a party service to organize a birthday party.

A child's birthday party may be held at his/her home or in a public place. Soft drinks and both sweet and savory foods are typically served to the guests. In many cultures, a birthday cake is served. Birthday parties for children often feature entertainment, costumes, and a theme. Adults' birthday parties in Western countries are often held in bars or nightclubs.

Surprise party

A surprise party is a party that is not made known beforehand to the person in whose honor it is being held.

Birthday surprise parties are the commonest kind of surprise party. At most such parties, the guests will arrive an hour or so before the honored person arrives. They conceal themselves from view, and when the honored person enters the room, they leap from hiding and all shout “Surprise!!”

For some surprise birthday parties, it is considered to be a good tactic to shock the honored person. Streamers, silly string, and balloons may be used for this purpose. Evidence of a party, such as decorations and balloons, are not made visible from the exterior of the home, so that the honored person will suspect nothing.

Parties for teenagers and young adults

Parties that are held by teenagers and young adults include house parties, dance parties, and outdoor parties. The term “house party” refers to a party where a large group of people get together at a private home to socialize. House parties that involve the drinking of beer pumped from a keg are called keg parties or “keggers.” These parties are popular in the United States and Australia but are illegal for persons under the legal drinking age. Sometimes, even older partygoers run afoul of the law for having provided alcoholic beverages to minors. Arrests may also be made for violating a noise ordinance, for disorderly conduct, and even for operating a “blind pig.”