What is FEESTDAG and why do we get happy hour all day on Stella and Palm on July 21st?

 In August 1830, stirred by a performance of Auber's La Muette de Portici at the Brussels opera house La Monnaie (Dutch: De Munt), theBelgian Revolution broke out, and the country wrested its independence from the Dutch, aided by French intellectuals and French armed forces. The real political forces behind this were the Catholic clergy, which was against the Protestant Dutch king, William I, and the equally strong liberals, who opposed the royal authoritarianism, and the fact that the Belgians were not represented proportionally in the national assemblies. At first, the Revolution was merely a call for greater autonomy, but due to the clumsy responses of the Dutch king to the problem, and his unwillingness to meet the demands of the revolutionaries, the Revolution quickly escalated into a fight for full independence.

From Wikipedia

http://en.wikipedia.org/wiki/History_of_Belgium#Independence