I have always loved clowns. Not the ugly misconstrued one from horror
shows, or the Simsons, but the funny cute, smiley ones like you find at a
children's party, the fair , the circus or rodeo. Some of my  favorites of
all times were Red Skeleton as Freddy The Freeloader

;  Charlie Chaplin,
as the Tramp; Laurel-and-Hardy; Bob Keeshan as Captain Kangaroo and
Clarabell;

What is a clown?

The word clown comes from words meaning "clot" or "clod" which came also to mean "clumsy fellow", according to the Oxford English Dictionary.
Clown is both a noun and a verb, and can also be an adjective (clown bike, clown shoes, clown white, clown gag and so on). Clown is also used to refer to anyone who provides entertainment in a clownish manner. Among professional clowns, "clown" often refers to the character portrayed, rather than the performer
According to the Encyclopedia Britannica, a clown is "a familiar comic character of pantomime and circus, known by his (sic) distinctive makeup and costume, ludicrous antics, and buffoonery, whose purpose is to induce hearty laughter. The clown, unlike the traditional fool or court jester, usually performs a set routine characterized by broad, graphic humor, absurd situations, and vigorous physical action".

The following is a brief history of clowning

The art of clowning has existed for thousands of years. A pygmy clown performed as a jester in the court of Pharaoh Dadkeri-Assi during Egypt's Fifth Dynasty about 2500 B.C. Court jesters have performed in China since 1818 B.C. Some of the earliest ancestors of the clown were present in ancient Greece. These comics were bald-headed and padded to appear larger than normal. They performed as secondary figures in farces and mime parodying the actions of more serious characters and at times threw nuts at the spectators. A similar type of clown also was present in the Roman mime. This clown wore a pointed hat and a patchwork colorful robe and was the target for all the tricks and abuse of his fellow actors.
Throughout history most cultures have had clowns. When Cortez conquered the Aztec Nation in 1520 A.D. he discovered Montezuma's court included jesters similar to those in Europe. Aztec fools, dwarf clowns, and hunchbacked buffoons were among the treasures Cortez took back to Pope Clement VII. Most Native American tribes had some type of clown character. These clowns played an important role in the social and religious life of the tribe, and in some cases were believed to be able to cure certain diseases.
In the late Middle Ages, the clown emerged as a professional comic actor when traveling entertainers began to imitate the antics of the court jesters and the amateur fool societies. The traveling companies of the Italian commedia dell'arte developed one of the most famous and durable clowns of all time, the Arlecchino, or Harlequin some time in the latter half of the 16th century. The Harlequin began as a comic valet, or "zany," but soon developed into an acrobatic trickster, wearing a black domino mask and carrying a bat or noisy slapstick with which he frequently spanked his victims.
The English clown was descended from the Vice character of the medieval mystery plays, a buffoon and prankster who could sometimes deceive even the Devil. Among the first professional stage clowns were the famous William Kempe and Robert Armin, both whom were connected with Shakespeare's company. Traveling English actors of the 17th century were responsible for the introduction of stage clowns to Germany, among them such popular characters as Pickelherring, who remained a German favorite until the 19th century. Pickelherring and his confederates wore clown costumes that have hardly changed to this day: oversized shoes, waistcoats, and hats, with giant ruffs around their necks.
The traditional whiteface makeup of the clown is thought to be introduced by the character of Pierrot, the French clown with a bald head and flour-whitened face. He first appeared during the latter part of the 17th century. He was created as a fool for Harlequin, Pierrot was gradually softened and sentimentalized. The pantomimist Jean- Baptiste-Gaspard Deburau took on the character in the early 19th century and created a famous love-sick, pathetic clown, whose melancholy has since remained part of the clown tradition.
The earliest of the true circus clowns was Joseph Grimaldi, who first appeared in England in 1805. Grimaldi's clown, called "Joey," specialized in the classic physical tricks, tumbling, pratfalls, and slapstick beatings. In the 1860s a low-comedy comic appeared under the name of Auguste, who had a big nose, baggy clothes, large shoes, and untidy manners. He worked with a whiteface clown and always spoiled the latter's trick by appearing at the wrong time to mess things up.
                                           
                      Joseph Grimaldi, "Father of Clowns" (1778-1837)
                         Inducted into the 1990 Clown Hall of Fame

Philip Astley created what is considered the first circus in England in 1768. He also created the first circus clown act called Billy Buttons, or the Tailor's Ride To Brentford. The topical act was based on a popular tale of a tailor, an inept equestrian, trying to ride a horse to Brentford to vote in an election
Grock (Adrien Wettach), a famous whiteface panomimist, evoked laughter in his continual struggle with inanimate objects. Chairs collapsed beneath him. When a stool was too far from a piano, he shoved the piano to the stool. His elaborate melancholy resembled that of Emmett Kelly, the American vagabond clown.

Jesters
Clowns who performed as court jesters were given great freedom of speech. Often they were the only one to speak out against the ruler's ideas, and through their humor were able to affect policy. The history of clowning is a history of creativity, evolution, and change. Harlequin started off as a Second Zany, the victim of Brighella. Performers portraying Harlequin gradually made him a smarter character until he eventually usurped Brighella's position. In English Pantomime
The first female American circus clown that we have records of was Amelia Butler who portrayed a recognizably feminine clown in 1858 while touring with a show called Nixon's Great American Circus and Kemp's Mammoth English Circus.

 A few more links            
                 Clown Ministry            History of Clowning