The biggest outdoor beer festival in the Baltics features multiple stages offering four days of concerts by local and international bands. The programme of events includes music from wall-to-wall, and the chance to hear popular local jazz performers, top rock bands and many other local and internationally recognised artists.
As you would expect there are variety of beers from all over the world on sale, and many restaurants and bars have their kiosks set up at the festival grounds.

Source: http://www.tourism.tallinn.ee/eng/fpage/experience/cultural_highlights#!4818_10664_1
Picture source: http://www.ollesummer.ee/est/pildid/2013_pildid/2013_reede#