I bought them a few hours ago, along with hundreds of other people trying to do the same, at the Portugal Bank...
The newest portuguese commemorative coin depicts a stylised image of Afonso Henriques, the first King of Portugal, together with his sword and the Castle of Guimarães, which is regarded as the birthplace of Portugal as an independent nation in the 12th century. To the left of the image is the Portuguese shield above the word “PORTUGAL”. To the lower right is the inscription “GUIMARÃES 2012” with the logo of Guimarães 2012 European Capital of Culture. Along the lower edge of the inner part are the mintmark “INCM” and the name of the designer, “JOSÉ DE GUIMARÃES”.