A Publicity stunt is a somewhat derogatory term for an event designed to create attention for a client, cause or larger event.
Publicity stunts can be, and often are, humorous in nature, but are always attention-getting. They are always somewhat adventurous activities done in front of the public to garner attention.
The "stunts" themselves may include give-aways, leafleting, costumes, or impersonations of famous people.
The name has become somewhat disreputable because they are often seen as distractions, rather than carefully planned PR campaigns that use mainstream methods and tactics such as mass mailings and traditional advertising. However, they often focus attention on serious issues and encourage others to act or become involved.
The term may be used to attack events performed by opponents in a political campaign or by business competitors.
They can be targeted to a certain demographic by being performed in a place where that market is located (such as at a convention) or designed to appeal to a large, undefined demographic. The latter works well when the issue - such as an anti-smoking campaign - is broad in appeal and will be understood by the target markets.
Examples of those who employ publicity stunts include thetruth.com, an anti-smoking campaign, and the liberal activist group "Yes Men," who often impersonate corporate spokesmen and create real-looking events to make their points.