The stamp is from the 2013 'Town Festivals' series celebrating the many small festivals held in Iceland (there must be lots to choose from because there was another set issued in 2014 which I do not have). Here is the FDC whose postal cancel shows the location of all the venues on a map of Iceland.
The festivals all involve food and music which must be quite perfect in those long days of summer in the north.
- Top left Gay Pride's six day festival first held in Reykjavik in 2000, concerts, events and a Pride Parade.
- Top right is 'The Great Fish Day' held in the tiny village of Dalvik in the north of Iceland when thousands of people turn up on the harbour in August and visit the local houses for free fish soup but not only the soup is free so are the rides, live music and folk dancing.
- Bottom left - Smelter Music Festival, so called because it takes place in an old fish smelting plant (called in Icelandic a "Bræðsla") in Borgarfjörður Eystri on the south west of Iceland.
- Bottom right - unlike the other festivals on the stamps this is not one is of recent origin but dates back to 1874 and the proud boast is that it has "never been cancelled due to weather or natural disasters"; a hardy lot these Icelanders. Held at the beginning of August when the Monday is a national holiday this is a long weekender in the Westman Islands and is described as "the most epic outdoor festival in the country". It sounds a bit like Glastonbury (but hopefully without the mud), everyone stays in tents and sings along to the music on the stage, the huge bonfire shown on the stamp is lit on the Friday night. The festival site and history here
An entry to Sunday Stamps II theme of - Making Music - more music makers here