Somebody asked about origin. This is pretty much the standard story.

Polka
Polka is defined as a vivacious couple dance of Bohemian origin in duple time was a basic pattern of hop-step-close-step; a lively Bohemian dance tune in 2/4 time.

The polka was originally a Czech peasant dance, developed in Eastern Bohemia (now part of Czechoslovakia). Bohemian historians believe that the polka was invented by a peasant girl (Anna Slezak, in Labska Tynice in 1834) one Sunday for her amusement. It was composed to a folk song "Strycek Nimra Koupil Simla (Uncle Nimra brought a white horse)." Anna called the step "Madera" because of its quickness and liveliness.

The dance was first introduced into the ballrooms of Prague in 1835. The name of the dance (pulka) is Czech for "half-step", referring to the rapid shift from one foot to the other.

In 1840, Raab, a dancing teach of Prague, danced the polka at the Odéon Theatre in Paris where it was a tremendous success. Parisian dancing teachers seized on the new dance and refined it for their salons and ballrooms. According to Cellarius, the famous French dancing master of the mid-nineteenth century: "What young man is there, although formerly most opposed to dancing, whom the polka has not snatched from his apathy to acquire, willy-nilly, a talent suddenly become indispensable?" Polkamania resulted. Dance academies were swamped and in desperation recruited ballet girls from the Paris Opéra as dancing partners to help teach the polka. This naturally attracted many young men who were interested in things other than dancing, and manners and morals in the dance pavilions deteriorated. Dancing developed a bad name and many parents forbade their daughters dancing with any but close friends of the family.

The polka was introduced in England by the middle of the nineteenth century. However, it did not achieve the popularity it had achieved on the Continent. By this time, it had also reached the United States. Thomas Balch, in his book Philadelphia Assemblies, reports that Breiter's band composed a new polka for the occasion of the 1849 Assembly. It was evident the waltz and polka were gradually replacing the contredanse and cotillion.

from here.

Cheers!
Ian