Laugh USA is a Sirius XM Radio channel featuring family comedy. The channel's slogan is "Classic Comedy and Good Clean Fun." The comedy aired sometimes contains mild profanities and slightly risqué material, and is only very rarely considered offensive. The channel broadcasts on channel 96 on XM Satellite Radio and on Sirius Satellite Radio (where it was previously on 105, replacing Laugh Break as part of the Sirius/XM merger on November 12, 2008).

Although there is much variety in the format, comedian segments commonly include Bill Cosby, Bill Engvall, Brian Regan, Carl Hurley, Chonda Pierce, Father Guido Sarducci, Gabriel Iglesias, Jeanne Robertson and others. Vintage routines can also be heard, including classics from Abbott and Costello, Bob Newhart, Bob and Ray, Henny Youngman, Mel Brooks, and Rodney Dangerfield, among others.

Before the merger in 2008 this channel featured a weekly mix known as the Comedy Piñata hosted by Joel Haas, where comedy was often delivered on a single topic, often seasonal, from various of its comedians' routines. Comedy Piñata was also known to highlight a single artist, whether by simply presenting a comedy concert, or in a format where standup comedy segments are woven into a sit-down interview presentation.

Laughing is a reaction to certain stimuli. It may ensue from hearing a joke, being tickled, or other stimuli. Most commonly, it is considered a visual expression of a number of positive emotional states, such as joy, mirth, happiness, relief, etc. However on some occasions it may express other emotions, such as embarrassment, apology or confusion ("nervous laughter)" or courtesy laugh.

Laughter is a part of human behavior regulated by the brain, helping humans clarify their intentions in social interaction and providing an emotional context to conversations. Laughter is used as a signal for being part of a group — it signals acceptance and positive interactions with others. Laughter is sometimes seen as contagious, and the laughter of one person can itself provoke laughter from others as a positive feedback. This may account in part for the popularity of laugh tracks in situation comedy television shows.

Laughter is anatomically mediated by the epiglottis constricting the larynx.

The study of humor and laughter, and its psychological and physiological effects on the human body, is called gelotology.

The United States of America (commonly abbreviated to the United States, the U.S., the USA, America, and the States) is a federal constitutional republic comprising fifty states and a federal district. The country is situated mostly in central North America, where its forty-eight contiguous states and Washington, D.C., the capital district, lie between the Pacific and Atlantic Oceans, bordered by Canada to the north and Mexico to the south. The state of Alaska is in the northwest of the continent, with Canada to the east and Russia to the west, across the Bering Strait. The state of Hawaii is an archipelago in the mid-Pacific. The country also possesses several territories in the Pacific and Caribbean.

At 3.79 million square miles (9.83 million km²) and with over 312 million people, the United States is the third or fourth largest country by total area, and the third largest by both land area and population. It is one of the world's most ethnically diverse and multicultural nations, the product of large-scale immigration from many countries. The U.S. economy is the world's largest national economy, with an estimated 2011 GDP of $15.1 trillion (22% of nominal global GDP and over 19% of global GDP at purchasing-power parity). Per capita income is the world's sixth-highest.